It doesn't matter whether they think it or not. What matters is if people keep creating crypto that require it (many have it as the initial phase in order to get their blockchain distributed and secured quickly).
When you're mining you have to understand what phase each crypto is in regarding EPOCH, Difficulty curve, POW>POS timings etc.
It's not point at one crypto and hope it lasts forever thing - there are many GPU mined cryptos and more coming, so you just need to have a bigger strategy and understand that watching the landscape and adapting to what's coming is part of the game.