Ethereum wants a PoS that works, so they will need to do something different. We don't know what that will look like. Other projects using PoS survive by doing

Ethereum wants a PoS that works, so they will need to do something different. We don't know what that will look like. Other projects using PoS survive by doing things like frequent block chain checkpoints (a notary stamped block if you will), which arguably isn't very decentralized or at least not trustless. If you have a notary anyway there are more efficient ways to go about things.