I've seen various comments on here suggesting that any fall in the value of BTC is the result of some conspiracy by the banks to make the price fall so that they can buy up all the BTC cheaply, and then get all the profits themselves.  The fact that anyone believes that betrays a fundamental misunderstanding of how Bitcoin works, and of the realities of the world.

So let's follow that scenario through.  Somehow, by manipulating the news the banks manage to precipitate a massive sell off where the price crashes to almost zero.  To do that, you have to convince all the HODLers that Bitcoin has no future, so they all cash out, and you can pick up their BTC for almost nothing.

So what are the banks left with?  A digital currency that no-one trusts.  If that's what they want, why not just save themselves a lot of time and effort, and create their own blockchain?

But that doesn't mean that the banks won't take over BTC - they'll just be much smarter about it.

What they'll do is simply press for Bitcoin to be under the same regulatory framework as fiat currencies.  They'll point to the scams, they'll point to the use by drug dealers, and in some countries they'll point to the use of BTC for illegal currency exports.  And they'll say "all these are reasons why all the normal banking regulations should apply to BTC".  And then they'll say that any entity that doesn't follow these regulations should be cut out of the system by making transactions with them illegal.

And this is what the majority of the population will want - they don't really care about the economic justifications for digital currency.  All they want is to be protected from scammers, and to feel that their money is safe.  And they trust the big banks for that, because by and large they've done a reasonable job of that.  (Bitcoin has a far worse record on bank stability.)

So the banks will slowly strangle Bitcoin, while making use of the technology with their own coins.  That's what they're already doing with Ripple, after all, where they're using the technology, but not the coins.

And maybe that's no bad thing.  If you truly believe in Bitcoin as an alternative currency, then the fiat link should be anathema to you.  Once the speculators have been squeezed out it will revert to its original intention - as a peer to peer currency independent of the financial system.  And your BTC will be worth just as much to you as they ever were.