Just tried logging in to coinex.io / coinexchange.io
And realized they don't exist anymore.
I never got any memo. Because they never sent me one.
If anyone knows how to contact them, please get in touch with me.
I would like my crypto back.

two words for you guy
volume popularity
they equal the same

That's a haiku to answer your question. I even double checked it.
Simply put: Volume = Popularity.
Can we agree on that? You can't have one without the other. If there is a huge volume changing hands, it must be a popular thing, yes?
Visit https://coinmarketcap.com/charts/#dominance-percentage and find on page "24h Vol". Look at that chart since the early days, the volume is at an unquestionable all time high nowadays (and always has been that way as time went on, actually).
So, again, to answer the question if Bitcoin is losing its popularity, if we look at it from the "volume" perspective, it hasn't lost it's popularity. It's gained and been a fairly nonstop train upwards and onwards since the beginning (arguably small speed bumps notwithstanding).
But still, even though Bitcoin is chugging along it's (slightly treacherous) rails, and doing great (volume is at an all time high) (volume = popularity, remember), it has "competitors", competing for, as you said, "popularity", or people's attention (money).
Now find on page "Percentage of Total Market Cap". Yikes? Maybe its losing popularity? Well, maybe not (remember the other chart?). So what's going on here? Some may argue that it is losing popularity when you look at this chart. Well, popularity in what? Many other things keep getting lumped into that chart as time goes on. Artwork? check. Cars? check. And just think, you can soon own any amount of mass of an old spaceship (or you-name-it) as you can afford! See what's happening? There's no limit to what will be dumped into the bucket called the "market". Everything from tokens which represent a fiat currency's "value", on down to cars and artwork, and everything in-between listed as tokenized assets and being traded on the markets. There's Trillions (yes, with a T) of dollars (USD speak here, sorry guys) worth of old-world "assets" headed to the marketplaces in the next few years. Are they really fighting for their "market share" away from Bitcoin? They got sent down that alley by default. Fighting among each other, that's for certain. Up until now it is (or was) Bitcoin against the world. So it is dwindling in that chart. New entrants to the exchanges, are on the other hand against Bitcoin. Hence the need for that chart. Its definitely a good topic, to watch Bitcoin dwindle when looking at enormous amounts of money flowing, let's say, to the blockchain. New "things" will be invented and added to that chart as time goes on.
On the other hand, who cares of the proportion of what kinds of things people buy at a supermarket - unless you run a supermarket! Apples, oranges, paper, milk, cookies, water, juice, soda, etc. What does a shopping cart consist of, what can we sell these people and how to arrange the store, the market, etc. Pair what near what, etc.
Bitcoin "market share" seems to go down when comparing it with those other types of things you can buy in those same marketplaces where you can buy Bitcoin. Thats what you should keep in the forefront of your mind when reading the "Percentage of Total Market Cap" chart. Then throw it in the garbage. If you run an exchange, determine trading pairs, god-like decisions such as these, of course it will matter more to you. But for an investor who is buying Bitcoin, and hoping Bitcoin goes up in value a lot faster than what they bought it with, maybe it shouldn't. The trading pairs at all the exchanges nearly all at least include a Bitcoin pair. Right now there are very limited trading pairs, it wont get more limited, but rather, it will become less limited as time goes on. Tomorrow's FinTech will eventually devour today's trading pair limitations and Bitcoin will be held in a different regard than it is today. Will that cause it to not be popular anymore? Not needed anymore? Needed for other things? Will any of it's current "competitors", and/or new entrants succeed with a better "product"; a super-Bitcoin built bigger better stronger faster cheaper (you name it).
Despite all that, one thing to me is clear, it is not at all losing popularity, according to the stats and facts, at least for now. Will it change one way or the other and what's going to happen, what events will cause other turns of events, and how things pan out.. for sure we will eventually see.

Thanks for sharing. This is big news.