Good for Rampage.
I'm honestly not a fan of him, but if someone wants to go do something else, then that's that. You certainly cannot fight forever, and unless you're making millions a fight, you're not getting paid enough to be settled all your life after your career is over, which he is not.
If he wants to try to get more movies/be a comedian, entertain, then by all means, he should do so. Hell, maybe he will join professional wrestling, I mean he's an entertainer and would be welcomed there I'm sure. You know how many fat guys that are in wrestling? Many. I'm sure he'd be okay hopping in the gym a few days a week to stay in decent shape to wrestle for the millions those guys get paid.