#3 Physical limitations
Kane is 51 years of age, and a large majority of fans as well as pro-wrestling experts have for long been calling for The Big Red Machine to hang up the wrestling boots.
However, I strongly disagree that Kane's age has much to do behind him being better off stepping away from active in-ring competition. In fact, Kane is extremely fit and agile for a 51 year old man.
Fans drowned out a popular wrestler with 'She's a racist' chants recently
Notwithstanding, it's the big man's future which seems truly worrisome. If Kane continues to tax his body by taking bumps after a career which has already spanned about 26 years, he'd quite likely have to deal with bone, joints as well as brain damage issues which several other pro-wrestlers have faced over the years...It's better to stop wrestling, than risk permanent damage just to prolong your career a little bit more...