Because the way they are implemented now is not real-time, they are merely snapshots: you can move funds to a hot wallet connected to the PoR snapshotting service and then move the funds away, loan them, etc. I think you get the idea.

It would’ve shortened the time it took for FTX to crash, but it wouldn’t stop it completely unless the snapshots are in a close enough interval such as every day — so that they don’t have chance to pump tokens.