Tyson lost 3-4 of his best year because of his conviction. Sugar Ray Leonard lost a big chunk of the 1980s because of a detached retina. Ali also lost some of his best years after being stripped of his title. Joe Louis record of defenses could have been even more impressive if WW2 had not happened. Could they have been even greater?
Ofcourse they could have been even greater without the "lost years". Most of them returned with less speed, stamina and technical abilities (as can clearly be seen with Tyson returning after 4 years of boxing inactivity).