The build-up for Tyson was much harder. His life was falling apart, he had problems with his promoter, King trying to steal him, wife trying to fake pregnancies, broke his hand punching Mitch Green in the face at 3 am, lost his trainer Rooney. That is why they had the match in the US instead of UK.
Tyson beat Carl Williams after this and lost to Buster so his peak was against Spinks. This fight with Bruno was the start of his decline and the worst performance as champion at that time.
The second fight Tyson had spent 4 years in jail and was a shell of himself. He was carefully managed and manoeuvred to make the most amount of money and avoid any dangerous fighter. Frank was an easy fight to pick up a title and then relinquish it rather than face Lennox Lewis.
True, Bruno tired in fights the later it went but Tyson knocked Bruno down in 10 seconds and stopped him in 5 and 3 rounds in their second bout. No version of Frank would beat Mike, styles make fights and Bruno was perfect for Tyson to look awesome. Mental health or no mental health.
A mentally sound Bruno in England would KO any version of Tyson within 8 rounds
Officially the only saddo who has had a girlfriend