Is Proof of Stake Really a Proof of Work?

Casper was supposed to be a proof of work chain and they used to notarize every hundred blocks or something. You can flip that on its head and have a proof of stake system wherever hundred blocks or every thousand blocks even is sort of notarized by a Proof of Work block. But then you still have to produce a bunch of proof of work making it probably you know intangible. Yeah I think there are some needs like actual technical solutions but practically like you're saying we trust no developers anyway so might as well hard coded in.