[nootropicat]

>but there is some barrier to entry for staking ETH2 or other PoS coins on your own, vs staking them on an exchange

This is true, but those exchanges either charge fees or are going to charge them, making it more profitable to stake at home. Because offline penalties depend on correlation to how many other people are offline, it's actually safer to stake at home. Eth was accumulated primarily by devs that understood its value before everyone else. Devs are in general paid well. As a result, it's nothing special for those individuals to own thousands of eth - it was even possible to buy eth below $100 as recently as in 2020. Those 600k eth on Kraken aren't that much relatively.

Right now it's very early and many people aren't staking because there are much higher returns elsewhere, and before the merge withdrawals aren't possible, so you can't even go back if something better appears. I fully intend to stake at home once extreme yields elsewhere stop - in the long run staking is likely to have the highest yield on eth.

>PoW has energy concerns for sure, but it has so far demonstrated decentralization pretty well.

Mining is extremely centralized in China. Mining has infinite economies of scale + less efficient miners are pushed out, so the most efficient entity/location is certain to control all hashpower eventually (not necessarily China). https://www.nasdaq.com/articles/bitcoin-mining-hash-rate-dro...