system
Given the following post, respond as if you're commenting on Reddit:
human
[Dragon Ball Super] Why didn't Jiren defeat everybody right then and there if he was that strong?
gpt
Jiren the Grey is an asshole.

You could make the argument that he was conserving his energy and stamina by remaining as his universe's "trump card" (or their second, if you count Topo going full God of Destruction), but mostly the thing is that for 95% of the fight Universe 11 didn't need him and he couldn't be bothered fighting all the different opponents, because he didn't need to. He took out a couple of the big threats, sized up the Saiyans and handed them their asses, and didn't care how much pain, stress, and heartache the other Pride Troopers suffered as they got defeated one by one. It wasn't until they very end when it was basically all down to him that he took things seriously...and that's basically why Universe 11 lost (which is almost assuredly a *good* thing in the grand scheme of things, because who wants to give that jerk a wish?)

But yeah, Jiren is an asshole. He's not a team player, shows no desire to help, talks down to *everyone*, wanted to do either nothing or everything.