The Eth POS will happen sooner or later.  It's been many years "pending" but one day it will happen.  And when it does, the shakeup wrt GPU mining will be huge.  Eth is the 2nd biggest crypto and the 3rd is a long way behind.  It's hard to imagine a scenario whereby all the hash power currently mining Eth turns to other much smaller cryptos, that doesn't result in a massive reduction in mining profits.

Crypto prices rise and fall, bull and bear markets come and go.  But the Eth POS will be an unprecedented event that will smash crypto mining profitability.  I just can't see any plausible alternative.  I would dearly love to be wrong and if anyone can logically and rationally detail a reasonable scenario whereby crypto mining continues to be at least half as profitable as it is now after the Eth POS, I would be very interested to read it.