"Blockchain" is probably fine. I suspect that it will eventually get some nice implementations where you want to be able to attest to integrity over time/space where multiple trusted parties evolve and change. A "distributed digital notary" if you will.
Cryptocurrencies as currently implemented (bitcoin and ilk) are eventually going to die for lack of a use case.
Problem 1: Most people like centralized authority of money. Most people like being able to get back their money when things get "stolen", for example. And people like reputation systems so that they don't get scammed (ie. illegal drug market).
Problem 2: Fees suck, but they're invisible to most people. Merchants hate fees, but you need users before that gets moving. We're also seeing that cryptocurrencies have non-trivial fees, as well. Funny that.
To be fair, traditional fees keep falling and some of that is probably due to cryptocurrencies. But some of that is simply trying to ward off the rise of a single digital purchase standard which would disrupt all of the incumbents. The payments space is a no-holds barred fight to the death and the incumbents would rather die than let anybody else get a foothold.
Problem 3: Cryptocurrencies aren't sufficiently anonymous. There is a use case for genuine anonymity. However, the current cryptocurrencies fail to be truly anonymous at blockchain as well as reality. Keeping your operational security sufficient to stay truly anonymous is damn difficult and having to go through an exchange doesn't help. Cryptocurrencies really need a decentralized exchange, but I'm not sure how that would even work. And, even if it did, since nobody could charge fees, nobody would have any incentive.
So, cryptocurrencies are mostly useful for people who fear central authority, are possibly concerned about fees, and only need to remain "semi"-anonymous. That pretty much describes petty criminals and mid-tier corrupt party bosses and ... not much else.