I would say Tobi wins, but Tsunade is a very real threat for him. The moment that she understands releasing chakra when she THINKS she'll make contact with him is only a waste is also the moment she stops releasing any of her chakra for attacks. I understand that Tobi's chakra constraints may as well be nonexistent, but they're still there. The guy simply isn't outlasting them unless he can find the opportunity to do major harm to Jiraiya and Tsunade multiple times as a method for them to dispense their chakra through healing. Pretty unlikely given how well Kakashi and Gai did against him.
Opposed to Tobi's useless state, the Sannin still can either bait Tobi or have hax ready for him if he doesn't take the bait.
1.Frog Song has two vulnerable & visibly plotting toads just begging for Tobi to attack them. They either snare him if he doesn't take the bait or becomes predictably tangible when taking the bait. Keep in mind that Tobi wouldn't know they're casting a genjutsu unless the dumb frogs actually say it in front of him.
2. It may be possible for Tsunade to give everyone her slugs and have the slugs reverse summon others/herself into Kamui if anyone is caught(this one's a bit of a stretch). Hell, it may be possible for Jiraiya & Orochimaru to share little frogs and snakes between each other and achieve the same thing. This would either discourage Obito from absorbing anyone if he catches on, or allow two characters to attack from the inside & escape Kamui if he foolishly sucks anyone up. Jiraiya can may be able to sense that Obito is gone & thus uses s/t jutsu to devise this counter & Orochimaru may have the analytical ability to reason this out as well.
If 1 nor 2 puts him down, he still isn't outlasting him.