Proof of Stake is fundamentally broken.

If there's a chain fork (which is the important corner case that Proof of Work is excellent at dealing with), there is no incentive for a Proof of Stake holder not to "vote" on both forks. This reduces network security substantially.

It also leads to the rich gaining more and more wealth over time.

Proof of Work leads to moderate energy consumption, but it's negligible compared to the utility of a Bitcoin.

I wonder how much CO2 it takes to make around $250 in cash?