PoS is no different from the legacy fiat financial system, where a small number of billionaires own 90% of the wealth. PoS is like a few megacorps owning the judge & jury, while PoW is a fair court trial where there is no conflict of interest.

The argument that 'a few mega miners own 90% of the network hashrate' doesn't work with GPU mineable coins like ETH. 90% of the hashrate is probably from miners who own less than 100 video cards. A quarter of the ETH hashrate is probably from gamers with just 1 video card.