Fine. Ali being reduced to a shaking, unable-to-speak husk of a person was the straw that broke the camel's back. It was the tipping point. It was the galvanizing moment. It was the reason mothers stopped letting their kids watch boxing.
The biggest star in the sport being reduced to a cuationary tale had way more to do with it than the alphabet soup of titles or the corruption of sanctioning organizations.
I'd go: 1. Ali's physical decline, 2. the generation that grew up with boxing dying off.
ETA: I agree completely with your latest post.
Honest question, do you have any evidence or research to back any of this up? It seems like after the fact conjecture, which has nothing to do with the late flag in Denver. I've never heard anyone reference Ali at the Olympics as a reason of boxing's decline and I'm a boxing fan. I'd put the reasons:
1 - Terrible title system
2- Terrible matchups - we've seen this for years where people can pick their opponents. This is why MMA has gone against this system and has mandatory matches
2a- Boring heavyweight / big name fighters - see Floyd Mayweather Jr.
3 - Pay Per View - combined with going to PPV and shitty matchups (see reasons 1 & 2) people weren't willing to pay. It works for MMA since they have great matchup on a regular basis and basically do the opposite of boxing.
4- Lack of dynamic boxers that aren't "Heavyweights". In boxing people for some reason love heavyweights, but most of the best fights are 140-170lb fighters but there's less KO's
5 - Corruption.
6 - MMA. MMA is providing what a lot of boxing fans have wanted and loved for years.
I've never really heard anything about Ali's Olympic appearance in Atlanta or his parkinsons as any reason for boxing's decline. I believe you're 25 or so? I was 14 when Ali appeared at the Olympics and I never heard a thing about the end of boxing because of it. What were your impressions of the 96 Olympics?