Another scenario is that banks start creating their own currencies based on the blockchain technology. You really think that people are going to prefer some of the existing currencies over the one that their banks say is the good one? They simply won't.
Actually, I think you touched the base here. Depending on how it will play out, we may have a serious financial revolution or a bubble burst and slow decline into a niche of digital goods for geeks.
Let's say is banks and governments will embrace blockchain & crypto.
Some (smaller countries & banks) will start supporting BTC, ETH or any other existing crypto. Why?
- easier to enter an existing market than create your own
- some of those 2014 BTC billionaires will look for an easy way to store & manage their assets - why not in a BTC-enabled bank?
- small countries may see it as a way to improve the well-being of their citizens
- when the rules change, opportunities arise and also in banking and govt world people know it and will try to take advantage
Other (big players) will rather go with their own. Why?
- rules change - take advantage (what I just wrote) - but why take someone else's rules if you can dictate your own?
- they will want to steal the wave and get even richer
- they will hope to take over the revolution, make it their own and then settle it down - so after few years, it's business as usual for them.
So in my opinion, if we want BTC to live on and actually change the way we are dealing with money, let's truly hop big players will be stupid enough not to embrace crypto until it is too late for them. Then I can see a chance for current small players become big players at crypto's back. And if a small bank makes it big because of e.g. BTC, it is less likely to reject it later on as it contributed itself to BTC popularization.
I hope you can follow my logic here and I didn't take too many shortcuts while laying that out