I think it's possible that Morphy would be at a really weird skill level where he would beat 2200 - 2300 players easily but lose to grandmasters every time.
I think I said this before on this thread. Morphy was really good at beating players even slightly worse than him, but I think he would have trouble against an opponent who really put up a fight. He wasn't used to having to make complex plans since any plan he made wouldn't last five moves before he would spot a subtle tactical mistake by his opponent.
@ Cherub_Enjel, totally agree with you.