This is a huge post, I see where you are coming from, but I will try to just say this.
"Prime" requires some degree of judgment. The reason why I put the word "prime" in quotation marks is it means different things to different people.
On one extreme end of a spectrum, if it is merely about reflexes and physicality, you could take a fighter in his physical peak, and claim he is prime, despite it possibly be him making his pro debut, or having never had boxing lessons or any display of technique. I would struggle to say that such a fighter would be "in his prime" if he later developed skills.
On the other extreme, you could have a mental and technical boxing genius, with greatly eroded physical ability. Again, it's a struggle to say he's in his prime. This seems to be core to your definition.
My view is a fighter's prime is somewhat judgmental. When you can say a boxer was consistently worse after being consistently better, that's indicative when a fighter was in his prime (excluding black swan type great or poor individual fight performances). And usually it coincides with the tail end of their physical prime. So I think of it as if you did a scatter type graph, a fighter's prime is where there is a cluster of his most impressive performances. For fighters that depend on speed, naturally they tend to have bigger drop offs when their physical prime ends.
For someone like Tyson, it's not an excuse, it's an observation that his technique and discipline went down the toilet relatively early in his career. It's not an excuse, or saying it's not a factor when thinking of his place in boxing history. It's simply an obvious obvservation. Was he physically shot from the toll of all the wars he was in? Of course not, but the cluster of his most impressive performances were early in his career years wise, and it was wonderful success and exemplary technique.
Guys like Lennox Lewis or James Toney are a bit different. If you plot their performances, you don't get the same sort of cluster, you would get a more dispersed type graph. For Lewis, because his skills evolved as he was much rawer as a youngster, and Toney because his style is heavily tilted towards old-style skill and counter punching.
I think your confused, the Prime I am talking about and this message boar, in this topic was referring to Mike Tyson"s physical and Mental Brain capabilities of fighting at his highest level and being able to compete at his highest level of talents, without age and natural loss of reflexes and timing do to the natural loses with age and the Human body breaking down and the Brain naturally losing it functions.
Your giving the definition of Prime being, when did Mike Tyson a state or time of greatest strength, vigor, or success in a person's life, start to end.
So we are using, two different definitions of the word Prime, answering this question.
My understanding of Prime, in answering the question is, the start of the end of Mike Tyson"s, best days, best years, prime of one's life, or ones, Boxing Prime years.
So if i take your definition of prime and your understanding of the question asked and the your answer given about Mike Tyson, starting to lose his Prime years , then your answer is 100% correct.
I also think or would assume, that my understanding of the question asked, when did Tyson start losing his Prime years and the answer i have given, is also 100% correct, scientifically and naturally, that Mike Tyson started losing his Prime years, do to age after his fights against Evander Holyfield, do to natural depletion of abilities, do to age and deterioration of Brain functions, resulting in loses and eventually retirement.
So we are both 100% correct, in our understanding of the question asked and both of our different answers given, so i don't see any problem whatsoever, just our understanding between us and the question being asked and the answers given.
