I don't think proof-of-stake will actually work. Not because of any technical reasons, but because 95% of the people involved in crypto just see it as a free money printing machine. Once their hardware is no longer useful for mining, they will just move to some other proof-of-work crypto.
It's incredibly unfortunate that Bitcoin and similar proof-of-work currencies blew up and remained hot commodities. Because I do think that cryptocurrency is abstractly a very exciting idea, but the popular implementations are fundamentally abysmal.
If proof-of-stake works out, particularly as a currency people can actually use, then maybe nobody wants to buy Bitcoin anymore and the whole thing dries up as only speculators are left.
Just to be clear, Bitcoin isn't creating any GPU demand now; mining ASICs are too good. Ethereum is also becoming ASIC-dominated, but being scrypt-based reduces the ASIC advantage.
