[SwagtimusPrime]

>because bitcoin users actually validate blocks

so do Ethereum users.

>In a PoS system there is an incentive for large stakeholders to increase block sizes.

this doesn't work because of Ethereum's social contract, just like it wouldn't work with Bitcoin.

Just because you stake a lot of ETH doesn't mean you suddenly have unilateral power to increase block sizes. There is a thing called consensus, and the entire community needs to achieve it to implement changes. Good luck trying to convince the community that bigger blocks that make it harder for small users to validate the chain is a good idea.