i believe it is mainly because each time that bitcoin makes a move (rise or a fall) all the traders in the whole market (note that i said traders not newbie bag holders!) turn their attention to bitcoin. this can be moving their bitcoins to BTC/USD market to sell before the bottom is reached and buy back at the bottom or moving their money there to buy bitcoin at the bottom if they have money which can be the money they gain by dumping their altcoins.
pulling money out of altcoins means they can easily go down. which is what happens each time.

they first have to be a good cryptocurrency that does an actual thing in the world and not just pretend solving problems and all the while get pumped and dumped for money making purposes. then we can see a serious cryptocurrency that is real, gains real adoption in real world by real businesses, and gains real solid price that doesn't just move down because bitcoin went up or down.

the problem is, so far we have had no coins with that description. they are all created for speculation and people also don't want them for anything else!

i think this is the biggest problem that we are facing these days. the manipulation at critical times. someone doesn't want the price to rise and they are doing all they can to keep it down.
i don't think we can get rid of whales ever, they are making a lot of money and will continue getting bigger only. the only way to fight them is to create a bigger market so that their size compared to the whole market don't matter anymore.

actually anybody who thinks "bitcoin is dead" (i wouldn't include altcoins in it because most of them are dead coins walking) is to blame because history is not something that is hidden away. it is easy to find and access. there are hundreds of sites and exchanges that have a chart showing the price history of bitcoin which they can easily look at. not to mention that they should not just consider price but also utility of bitcoin which has been increasing every day. it is about all the merchants that have been accepting bitcoin as payment, all the millions of dollars that is being transferred through bitcoin on a daily basis! and a lot more.

 it is possible that some newbies go look at coinmarketcap to make their decisions for which coin to buy or not to buy but the market meaning the majority of investors and the market makers aka altcoin pumpers in this market, don't care which coin is listed where. they only look at its charts and stats such as its volume, price and where that price is, hypes in the media, potential of pumping,... and then pump such coins that meet their criteria.

you are getting two things wrong here.
first one is the fact that bitcoin is always set for a bull run, even during its correction drops it is getting ready for the bull run because the demand for it is constantly increasing even when newbies are being flushed out.

second is the fact that you think altcoins should rise with bitcoin! in fact the exact opposite has always been true meaning whenever bitcoin goes up altcoins go down, some of them even drop hard. in case of ETH, it is not an exception. this coin will also go down like other altcoins specially since it is overpriced by a lot.

i wouldn't call this a "Bearish sentiment" just because price didn't go to the moon because it is not dropping either. it is above $7k while it was below it before this rise happened. but i agree that everyone seems to be waiting for the SEC decision about ETF so that they can decide which way the market is going to go and go with it.
the only problem that i see is the fact that SEC is delaying ETF and pushing it back so this trend may continue for a while!

LOL. i think OP thinks the "government" is a kid with ADD who you can distract easily by dangling your key chain in front of them

not to mention that all the negativity that altcoins have brought to bitcoin. for example last year's ICO scams which go to billions of dollars scammed out of people's pockets have caused a lot of issues. the smallest of which have been banning of all crypto related ads on big platforms such as Google and Facebook. not to mention all the illegal pump and dumps that are happening every second in the altcoin market.

no we don't need payment processors. in fact the notion of a payment processor for a decentralized currency that was created so that we don't need a third party middle man is kind of absurd if you think about it.
but because of volatility and the fact that merchants (for now) want fiat more than bitcoin, means bitcoin payment processors such as BitPay are a thing! in the future as bitcoin becomes more popular and acts more as a currency and also becomes more stable after reaching mass adoption, we can see payment processors become obsolete. although we have many years till that time.

i don't know how much money some people have to lose before they stop chanting "have patience"!

it really doesn't matter how much you sugar coat this, in the end you are encouraging people to bag hold while getting dumped on. and the result is a huge loss, a prolonged bear market and a bigger downtrend.
instead if people dumped like they always dumped in previous years after each pump, we would have already gotten out of the bubbles and were starting to see the summer pumps that are common during this time of year in altcoin market.

no, Vitalik dumps his free ethers only on top of the bubbles and he is already a millionaire out of thin air he doesn't have to dump at the bottom.

however, what is happening as you may already know is that the bubble is bursting. as a matter of fact it has been bursting for a while now but the drop has been slow mostly because of the hype that is going on. people are trying so hard to prevent the crash but they can not.
on top of that we have the death of ICOs which means there aren't as many of them as before and the old ones are making their exit by selling their free coins to get out with the most profit.

in my speculation real price of ETH based on this situation and its massive supply should be under $100 and until we reach there we won't see a proper market.

i think this is mainly the correction of the super hyped up ETF's FOMO buy combined with a lot of manipulative dumps at $8000 to push the price lower which succeeded. and when that was broken the market reacted to that drop and continued on a downtrend.

it still isn't big so i wouldn't worry about it unless we start seeing $6k again and try testing the bottom.

majority of altcoins serve one purpose and that is to generate money for their investors aka speculators. with or without bitcoin they may exist because pump and dumps don't just go away. people are making a lot of money from them! besides they are mostly useless already if you don't count what i just said as their usage.

ethereum is in no way "second" it is after at least a couple of thousands of different altcoins!

that is the only reason ETH exists and the only reason it is this pumped up. because it offered a very easy way of creating tokens out of thin air which you could offer in an ICO and earn a shitload of money. so it attracted thousands of scammers and people who wanted easy free money to itself.

there was a topic that was deleted because OP of it was advertising shitcoins, in there he was insisting that ICOs are "solving problems". i asked him to provide an example of at least one and he failed. i ask you again. what is the usage of Ethereum? creating ICOs. what is the usage of ICOs? what have they solved? nothing. prove me wrong!

this is more than enough to make it possible. because it will basically be the same as fiat and bank accounts. people are using them and they wouldn't mind switching to blockchain or cryptocurrency. they may not even know it and whilst using the same bank account they had they may be using cryptocurrencies.
but no matter what you do you can never replace ALL forms of payment. people want other options so they will always use other options including decentralized currencies such as bitcoin.

do you see anything changed about bitcoin? of course not.
bitcoin is still the same decentralized currency that has no match in the world and it still also has the same limited supply while its demand is increasing.
there is no way to prevent the price of this permissionless currency from rising back up! you can always delay it and cause dips in short term but in the long term the market always wins.

as soon as you (and people like you aka bag holders) stop holding these altcoins!

that is the problem that we are facing these days, specially in the big market cap coins. the market is on a downtrend and the drops are inevitable but the bag holders keep on delaying it by their panic actions.
for example imagine an altcoin which is worth $1000 but it is supposed to be worth $100. the drop starts and price goes down to $900. the bag holders hold on tight, then the drop happens again and price goes to $890 then they panic and dump their bags and price goes to $850 but because it was a big drop there are day traders who buy the bottom to make a profit in short term so price recovers to $880, the bag holders seeing this jump back in and start buying at a loss and price goes to $890 but then after the dead cat bounce was finished the drop continues and price goes down to $800 this time harder because those day traders would sell on top and that triggers another panic sell.

this is repeated a lot of times so the drop is slowed down like what you see now and won't complete unless price reaches the real bottom.

bitcoin market is mainly waiting for something to start the rise. and that something is ETF, its rejection or approval doesn't matter. what matters is that it is currently acting like a roadblock for bitcoin's rise. if it is approved then we will see a big surge and a follow up correction delaying the main rise. and if it is rejected then the FUD will pour in and there will be a drop again delaying the main rise from happening.

as for altcoins you named, they aren't exactly under pressure. they are simply having their dumping phase and going down. ETH went  down to $419 and will soon try to go back to $3XX levels. BCH is struggling to keep its volume up and despite the pump attempts it is still on a downtrend currently reaching $757 and trying to go lower. and finally XRP is still in a huge bubble needing to go lower to 1000 satoshi levels which is 1/5 of its current price.

every fake hype, every pump, every manipulation, ... have an expiration date.

if you look back at the history of altcoins, every now and then we have some major way of scamming people and taking their moneyz! for example not so long ago a famous way of doing it was to premine the altcoin you release so that you own a large number of the coins you release and then let others come in. as they came you dumped all the coins you created out of thin air and make a lot of money. people were falling for premine coins and every day there were new ones coming out.
eventually they caught on and stopped investing in these type of shitcoins.

now the same people have moved to ICOs. and the days of ICO is starting to end.

i missed it but it seems to me that it was some whale wars going on yesterday. someone was pushing down the price all day yesterday to bring it down to $7k levels despite a good buy support to keep it above $8k and maybe other whales disagreed with this push down and started trying to prevent it by placing these fake buy walls that were moving and never being filled. in any case they weren't that successful since we are currently at $7.5k!

being first is not the reason why bitcoin is still on top. in history there has been a lot of new things like bitcoin that started as the first but soon they were put aside and were replaced by better things.

the reason why bitcoin is on top and will remain there is because it is working much better than any alternative. it is because bitcoin is the most decentralized and most secure currency that you can hope for. it is because bitcoin is actually used as a currency in many places. and a lot more reasons like these.

as for altcoins they didn't start like this. in fact in early years we only had a handful of them and each of them had a very interesting idea which they were exploring. they were really alternative cryptocurrencies. but nowadays there are 1700+ altcoins in existence and more than 90% of them are useless shitcoins specially the coins with the biggest market caps.