Earlier quoted context omitted.
I am not convinced that PoW is immune to those pressures or even resistant to it. The people with capital control the mining. At least the environmental problems are reduced with PoS
The difference is that PoW is censorship resistant. Anybody can be a miner and existing miners cannot censor new miners. Performing new work is external to the network state. In PoS, existing stakers can prevent new stakers from registering. Very important distinction.
Existing PoW miners can fork away from any new miners that won the last block.