Today Net Hashrate
ETH : 600 TH/s ~ 20.000.000 RX 570 8G
RVN : 5 TH/s ~ 384.615 RX 570 8G
ERG : 15 TH/s ~230.769 RX 570 8G
If ETH go to PoS, you will see all PoW coins become unprofitable. And 60-70% miners will left
How much of this hashrate do ASICs or fpga take?
Ethereum 2.0 hasn't even been tested yet. It is possible to increase the time frame for changing the algorithm.
Perhaps the developers have not yet prepared a new coin for miners

Many people were mining with a profit of 20-30 cents per day from one video card.