I think the boxing analogy is a good one, even though college boxing was never as popular or lucrative as football. According to
this article, intercollegiate boxing was a really big deal in the 1930's, 1940's and 1950's. Some matches drew as many as 15,000 fans, i.e., more than twice what Rutgers averages for men's basketball

But injuries and some high profile deaths caused most colleges to rethink their sponsorship of boxing teams, and the NCAA dropped the sport. That happened even though the college boxers were using headgear and heavily padded gloves, and had relatively short matches. According to
this article, SU was one of the last schools to drop the sport in the northeast.
I see CTE as the biggest threat to college football. The equipment, concussion protocols and other rules may need to change for the sport to survive at the college level, IMO.