How on gods green earth is Edo Madara going to run out of chakra for orochimaOro to take over his body?!?
Never in history has a simple curse mark been able to take over anyone's
Body. Not without them completely running out of chakra.
Madara has already stated that he regenerates and is immortal. I don't see where you're going here with this curse mark logic sir.
In my honest opinion, this statement seems more legit than what the OP has stated.
Anyways, after Jugo & Suigetsu confronted Sasuke, they told him that even though Itachi & he stopped Kabuto’s Edo-tensei, Edo-Madara is still around. Sasuke was shocked & said, so, he is still around. It seems he was talking about Orochimaru this time. Then he had a background memory of Itachi & Shisui with lines of protecting the village & the Uchiha names or whatsoever. At any rate, I think that the very reason why Sasuke needed to meet up with Orochimaru or concluded that he was still alive was because he thought Orochimaru was the one who revived Uchiha Madara. This will be his own assumption as to why Edo-Madara did not vanished as compared to his brother. Sasuke wouldn’t know that Madara knew the seal or he could break through the Edo-tensei jutsu. Thus, he’ll be going for Orochimaru to certainly stop Edo-Madara for the sake of Itachi & Shisui’s name.
Edit: This is a discussion forum so I’m not going to argue with anyone’s statement. I’m just expressing my thoughts with regard to this matter. Peace!
To OP: This is a very nice theory, & it's quite fair to assume that you have a good observation. Decent thread, well written & you explained all the details thoroughly. +rep for the effort.