Enforcement would be tricky. Fleeing wealth might be a real issue at that level of taxation, and you'd have to stop all kinds of activities that the really weal

Enforcement would be tricky. Fleeing wealth might be a real issue at that level of taxation, and you'd have to stop all kinds of activities that the really wealthy use to avoid the inheritance taxes we already do have (family trusts, board membership on corporations that exist largely to buy housing and transportation for family members, plus all sorts of overseas shenanigans and likely plenty of outright illegal maneuvering)