Proof-of-Work and Proof-of-Stake have both their positive and negative aspects. I won't go into details, but I suggest you to watch this video from Jackson Palmer (creator of Dogecoin, among other things) about PoW and PoS.
However, saying that Proof-Of-Work is wasteful is a terrible mistake. Of course, miners should look for alternative sources of electricity, switch to green energy and, maybe, move to countries where there is a surplus of electricity. Moreover, mining equipment producers should work on more efficient ASICs.

However, I do not think PoS will replace PoW since it means Bitcoin should be replaced.