That's not true, Fighters prime means their reflexes and timing being at their peek and no noticeable Brain trauma being detected, just losing focus and being lazy is not being out of Prime.
Mike Tyson was still in his Prime after Buster Douglas because Mike was still able to capture the Heavyweight Championship and the only reason why he lost it was because he happened to fight a better all around Boxer in Evander Holyfield and lost to him twice with Holyfield beating him easily and knocking Tyson out in their first fight and that's why Tyson lost, not because he was past his prime.
Being lazy and not mentally focused doesn't and has nothing to do with being past prime, but some Boxers even all time greats lose their skills and medal abilities even at a young age of their careers.
James toney being an example of a lazy fighter but not past prime and still went up to Heavyweight and won a title but after being stripped of that title and even beating Holyfield and after losing the title still fighting and beating top big Heavyweight contenders coming up from Middleweight.
James Toney"s mental focus and bad eating habits and laziness, having him lose important title fights have been discussed and no one ever says Toney was past prime after those loses.
So why does Mike Tyson get this excuse from certain fans?
Example of young world champions prime boxing years ended early at a young age, do to to much head trauma, or lose of reflexes, which we call in boxing being a shot fighter.
Mildrick Taylor, shot fighter after Chavez, prime years lost early in his career.
Riddick Bowe, shot fighter early in his career noticeable slurred speech after the Golota fights, having to retire due to much head trauma, even though he was lazy, you can't ignore the noticeable slurred speech and massive head shots in the wars with Holyfield and against Golota, just listen to his speech after the second Golota fight and everyone was saying he should retire, something isn't right, Lue Duva was screening this to HBO and the fans.
Adrian Broner a world champion is now a shot fighter at a very young age, not being able to pull the trigger and everyone notices this, just like Mildrick Taylor.
Muhammad Ali, lost his abilities at a young age losing his prime abilities early because of Parkinson"s disease and trainers noticing this during the Joe Frazier fights, it has been documented by quotes from trainers. Doctors even saying it could of started earlier in his life.
Some Boxers lose their Prime years earlier then others, but Mike Tyson wasn't a shot fighter at an early age, he just lost to a better fighter that night, then went to prison and did his time came back and won a championship, then lost to a better fighter again twice, then started losing his natural reflexes and timing due to age, losing again to Lennox Lewis and then was done as a fighter.
The problem is people don't want to admit that their favorite Boxer happened to get beat by a better fighter then himself and just make excuses that he was losing his Prime early due to losing mental focus, but that's not losing their Prime early, it's just being lazy and stupid and this isn't a valid excuse for anyone.