madara vs gai was just too full up time untill sasuke& naruto where back.Would it have helped against madara or would madara have still survived? Madara says that he almost died but I think he could have taken so much more.
Then why would he state that Gai almost killed him?No he couldn't have changed the outcome. Madara can't die just from taijutsu (even at that ridiculous level) he needs to be sealed away in order to lose.
As Sasuke demonstrated, even cutting him in half did NOTHING to him, he still used Kamui and regenerated it all back.