IMO it had nothing to do with age, this fight had to have been 100% staged. There was never a plan for Mike to win, or knock out JP. It seemed obvious to me, lawyers and contracts got in the middle of this fight, which turned out to be nothing short of a business agreement. Reports of JP getting 40 M, and Mike 20M.
I've been following the fight game for several decades, and Mike's career since he was a teenager. It did not appear to me that he even made a single solid offensive maneuver on JP. He just danced around for 16 minutes. Last night we saw Money Mike, not Iron Mike.