Its been more than 100 years since the fight between the First and Madara. And Pain is not that old, he is i guess 30 or 40. So keeping Madara alive all this time is not possible. The reason Madara was upset that Pain used the life jutsu on Konoha is that Madara thought that he can use Pain's jutsu in the future if he needed it.So your reason for Madara's survival can't just be possible. i want your views on thisHe survived for so long because of pein lol thats why he was pissed when he used that life jutsu on konoha hahaha but yeah pein kept Madara alive and well all this time by "killing him"
and using the technique to ressurect him or so i'd choose to believe (makes sense to me bro)
For the same reason the 4th sealed the fox in Naruto lol don't forget bro the frist could control bijuu like pets and this is what prolly fockt madara's day up the konoha Kage's i'm sure know all about the history of one another and it stands to reason the 4th sealed the Fox into Naruto after getting a "lucky shot" on Madara forcing him to retreat. ( We do know the 4th fought Madara and the Fox at the same time so Naruto's dad has some Teaching to give his boy)
I WOULD LOVE ! ! ! kishi to go spend some time and show these fights and not just eye rape us with sasuke all the time !!!!! so to speculation of what might have happend..
SO my guess is like this the frist and madara square off they go back and forth and then start busting out powerhouse moves madara with EMS and the frist with his landscape of doomhe prolly figured Madara out that he deflects all attacks but needs to be soild to land a attack then Madara summoned the Fox (Only known shinobi who was powerful enough to do it) and thought to use it on the frist but he fliped the fox on Madara well he was going to bust out a end all attack and in this suprise he landed a near fatal hit on him ... thus leading to the rest the frist walked up saw he was "dead" or so he thought madara knowing his end is near decided he'd use izanagi and give up his sharingan to get even with konoha and the frist in the future,,,,
From that day onwards he has always worked in the shadow's mindrapeing sasuke and the rest of akasuki using there power to gather the tailed beasts and become the 10 tailed jinchuriki and use sasuke's eyes to get his powers back "and become complete" as he said in the kage summit lol
ALL speculation mind you but i see the battle going something along these lines