People with more can stake more. Over time stakes will get bigger and bigger.

Well, it's still fair in the sense that everyone has access to the same rate of return, if they choose to stake. (And in some modern PoS designs, staking nodes can be run with very little resources.)

Consider a hypothetical blockchain where every account is subject to a tax of 10% per year, and the proceeds are burned. One might say that everyone is getting poorer, and the rich are getting poorer at a faster rate.

But of course there's no real difference. If every account receives a 10% reward or a 10% tax, we all end up with the same share of the token supply at the end of the day.

The current minimum stake is $50k and will likely only get bigger over time as there’s more people willing to stake than need to be staked.

So it’s already really exclusive as only a very few people have $50k available.

Eth2's design supports staking pools though, so it just takes ~$20 to participate, depending on the pool. Granted, some of the staking rewards go to the node operator, but it's a competitive market, so the difference should be comparable to the costs of operating a node.

There are also some sharded PoS designs where staking can be done in a really lightweight manner -- the process can be mostly idle, and only sync when it's the user's turn to do something -- even on a mobile device.