Another is that, unfortunately, Bitcoin has still not fulfilled its promise to be a usable currency.
while it's true satoshi described Bitcoin as a peer-to-peer electronic currency, I think the design is more suitable for store of wealth and probably a transaction which requires a very secure confirmation. as Jet Cash mentioned, from the beginning security and confirmation is more important than scalability/speed of transactions.
Murad Mahmudov argue that the first layer of Bitcoin is more appropriate or suited to move/transfer assets in a large amount, so that they benefit from a relatively low fees and very secure confirmation, while the second chain and so on will be much faster. it's more or less similar to how we transfer/move gold, while the second layer with gold as the basis (paper money) is much faster but less secure (you can fake it).
i think the reason Bitcoin price dropping lately is because in general, Bitcoin is viewed as investment. a lot of people in the late 2017 join the ride and some of them exit it when the price reach its peak, buy pressure got weak because there's no more people who wanted to join the ride and then sell pressure increase. sure, bitcoin network, development and so on is going on, but the public doesn't care about that, because they want to make profits in the shortest amount of time possible.
the delay of Bakkt and ETF, and other news, can fuel negative sentiment in the market (even though it's irrational). it's like a snow ball, one people tell this is bad news, and others start to consider that and they exit or sell bitcoin to avoid further loss. on top of that, it's hard to separate crypto/Bitcoin from pump & dump scheme at this moment because several actors makes it go that way. for example, the over hyped Bittorent which is now trading at 4x even though there's really no use for this token proof it.
lightning network is good, but people who use it is not so many. i bet there's a few of us who use lightning and there are more people who trade/speculate with ico. because of this, the majority will always be those who're so easy to get swayed by bad news and doesn't care about development, which in turn will sell or buy when they feel they can gain something from it.
just my 2 cents.