Maia has shown the ability to doggedly pursue takedowns for 3 rounds. I think if the fight isn't over by end of rd 3 it's doubtful he'd have much left in the tank at all, but assuming he only has one round of cardio is way off. He's done it for 3 rounds multiple times.
Sub probably is Maia's chance to win, I agree with that. But it's a pretty good chance. You are underrating him a lot. Yes Woodley could land a bomb at any time and finish, no doubt. But Maia's ability to get ahold of the single and drive through to the hips is elite. And while I agree Woodley probably will be a bigger challenge than Maia has had in terms of his athleticism and ability to sprawl, Maia has shown he's playing chess with his grappling while everyone else is playing checkers. He is a master at taking an inch of space at a time, until (as
@Shoulder pointed out) he "magically" has his opponent's back. But it's not "magic", he just is a step ahead in where he moves when his opponents react to what he's doing. It's why you see him take so many guys' backs even without getting the TD. He'll run the pipe as well as anyone, but then as his opponent adjusts and even begins to turn his hips to stay on balance, Maia will slide outside a bit and force his opponent to make a choice. And he feels their movement and simply adjusts better and faster than anyone else.
Once he has ahold of the single and has closed in, you are in survival mode. You are defending being dragged down by the single but also simultaneously defending him sliding around and taking your back. And he's better at that game than you are. Now Woodley may just have the strength and wrestling to shut it down. Maybe. Or maybe he lands a bomb before he has to defend it. But if Maia gets the leg and runs the pipe, it could be the beginning of the end. Obviously Woodley can't give Maia his back, but nor can he get dragged to the mat and end up on the bottom. He may not be able to survive on the mat all that long vs Maia. I can't remember if Woodley has grappled much with any good submission fighters, but I cannot believe he has the chops to survive long on his back vs someone of Maia's caliber.