I think that he improved right up to the second Corbett fight. It is even possible that he could have got better after the Munro fight, had he decided to fight on.
Why thank you my friend! I'll let you know how I how I feel later tonight ,after1/2 a bottle of red and a couple of Singha beers with a slice of lemon in them!
And you base this on him beating up a third rater in Munroe, and a terminally shot Corbett whose seconds had a pre arrangement signal with the referee to stop it on this agreed signal?
I base it on what contemporary observers said. Even if he did not have his best opponents in front of him, people would be able to tell if he was doing things that he did not do before.
I entertain that possibility, but you seem to be unwilling to entertain the more alternative/obvious possibility, that he simply improved as the contemporary observers said!
A hell, of a lot! While Jeffries was champion, every newspaper with aspirations, sent a ringside observer to his fights!
Have you come across any particular reporters who documented his career that way, noting his fight-to-fight improvements in real time? Any who stand out as especially credible and convincing? I've only looked into this in passing but I get the sense that a lot of old-school boxing writers relied way more on hearsay, gossip, the reporting of others, and the wisdom of crowds more than we recognize. I could be wrong but I suspect that most of the guys who commented on these early fighters only actually saw a small percentage of their actual bouts. The other thing that stands out is that some of even the first-hand accounts are flat-out incorrect. A shame those guys didn't have tapes of the fights and video replay!
And watching him dispatch the hapless Munroe and the totally washed up Corbett led them to declare **** ME, OLD JEFF'S IMPROVED NO END!
He was, but fighters throughout their primes kept improving. Remember that Jeffries didn't have much of an experience before turning pro, so he gained it after every win. Again, it's similar to Marciano who needed a lot of fights to become the best version of himself.