Nowadays many projects are aim their consensus to be a PoS coins. Most of the miner now mine Ethereum with a possibility that Ethereum will turn to PoS and they cant mine anymore.
It's not just a possibility but it will actually happen that through this 2.0, Ethereum is about to turn from being PoW consensus to PoS.Also the diff is really high and 4gb GPU became weaker to mine Ethereum, you need GPU with more than 4GB. So if you want to do mining, think twice 
Yeah this is true, 8gb and above should be your GPU this time to make it profitable and there's another problem, I don't know if it's the same problem in op's location but there is again shortage in GPU for particular areas/countries.