More realistically it would immediately create a fork in PoS
Agreed. Pow incentivizes time/energy spent on the thing that one already did spent time/energy on (which is also why there will never be a 1:1 copy of bitcoin). Pos does not have this natural self incentive. In any ethereum fork people can just stake on both forks which is detrimental with ethereums centralized foundation and a demi-god vitalik.