I have not watched the fight yet due to IRL events. But just from personal experience defending against a rear naked choke and guillotines are one of the simplest things to do(Saying that the defensive action is simple actually stopping the choke is another story) and taught very very early in many martial arts also most trainers will pickup on it easily and its not like I get advice from UFC trainers, So I can only assume his trainers are a lot smarter.
As you said people can defend against them a long time. I have sat in one where they never got the choke but held me down so long and hard there thighs bruised my ribs.
On that note I doubt he just let it happen usually the opponent will pull a little move to get them off balance or just drop concentration so they can get under that chin.
Some things you can do to lift that chin are very annoying. All your concentration on keeping your chin down while there squeezing your ribs like a snake. Its tap, Take a breath and get choked or against someone like Tito option three would be let his legs break your ribs lol
