Another issue with PoS is lack of commitment.

A PoW miner has to plan ahead, crunch numbers, prepare the operation, install ASICs and cooling, etc. and in the end they can't just dump their ASICs any time they want and buy it back later if they changed their mind. If someone starts mining something like bitcoin, specially with large operations, they commit to it. "In sickness and in health"!

In case of PoS they have no commitment whatsoever. They can buy the coins and become a big stakeholder with virtually one click and at any moment they can dump it and get out. For example if the PoS coin starts dumping they can sell it immediately effectively abandoning the coin.