I am also wary of proof of stake, but this is not something you can say with such a certainty, like you're doing.

If someone asked "how safe is proof of work?" ten years ago, everyone would have laughed and thought you're joking.

I'm only saying this because you're making a snarky comment while pretending to know exactly how it will play out. Nobody knows how it will work. Who knows? Maybe some unexpected human behavior like mining pools will happen in proof of stake approaches and it may end up going in a completely unexpected direction.