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.
Why shouldn't bitcoin be replaced? Just because it was there first does not mean it is good forever
The greatest deveolpers are working on it, I do not think they will easily switch to another coin. I may be wrong, of course. Let's what happens!
at some point almost everybody will have switched, and the talk you take for wisdom is preaching to a sectarian choir. I'm curious if that's not already happening.
So, where are the devs going now?
What I have been seeing is people working hard to solve Bitcoin problems. Despite the forks, despite all the coins that claim to be the next bitcoin, the real Bitcoin is still here. This is not a sectarian choir, as you said. It is something you can easily see by yourself.
I expect plenty of Bitcoin developers have moved on to set up other coins when they see better technology options. Bitcoin is brilliant technology, but I wonder if the founders foresaw the impact it would have in resources before it's even become an everyday thing for most people. It just cannot carry on as it is now.
I should mention that the article is not about Bitcoin as that is not viable on GPUs and uses dedicated hardware. That still needs replacing regularly.
At the very least we should be harvesting heat from mining rigs to warm homes or generate power.