I'm assuming you mean Mike Tyson, and the revisionist history surrounding Iron Mike goes in the opposite direction. People nowadays tend to think he was better than he actually was. Pretty much no boxing historian thinks Mike was the best HW of his generation, and certainly not one of the HW GOATs; yet plenty of casuals think he's in the GOAT discussion, or that he would have been if he didn't go to jail. Teddy Atlas, Mike's former trainer, explained it perfectly on the JRE. Mike had amazing physical talent, but he didn't have the mental makeup to be one of the greats. He was the classic front-runner who looked like a world-beater against over-matched competition, but he'd come undone when faced with resistance.