No, I was told it would happen when I was an adult. I am now 47 and it is still only a quirky and finally piece on the news. Until I am moaning that I was caught up in a jetpack jam, and was five seconds late getting home, I will not be happy!
The quality of the champions would increase, but so would the quality of the challengers. I doubt anybody would hold it for ten years.
There are probably limits to how much more skilled somebody like Dempsey or Louis could get, though, even with perpetual rejuvenation. (And limits to how much of a performance difference the skill would make.) Once they start weight training in the late 80s or so, you'll see permanent strength gains climbing up to a point (kind of like how modern fighters can keep adding strength into later life artificially), but again, that's probably going to run into a limit eventually.
Whichever eras you favored, the talent would pile up until it became ridiculous, and everybody would be more hungry than the man who held the title.
That's true, but conversely, you only need to hold off a contender from the title for long enough to run their biological clock down. If you lose the title to one of them, you've got yourself another perpetual opponent to add to the list. Challenger selection will be very careful, I suspect. If somebody with phenomenal talent gets the title, and if he can reliably beat a couple prior champs, he can try insisting on eliminators that include those guys. And all the perpetually young former champs would probably have a tacit agreement to do the same if they get the title again, since it's in all of their best interests not to add to the club. Tunney probably would have come up with a cartel structure by the 20s if he'd managed to beat a rejuvenated Dempsey. The very interesting question emerges about what happens when the Mob tries to fix title fights.
I think that history shows us, that even a strong champion in a weak era, will encounter some sort of effective resistance i.e. Joe Louis. An era where all of the top fighters are strong, should be almost impossible to maintain consistency in.
I wouldn't be so sure Louis fought in a weak era. What's our evidence for that, aside from Louis murderizing all the top contenders?
That's a good point, and we might even see some take a few decades off and then come back for another career. That's another interesting possibility.
I am sure Al Capone would want that sweet sweet immortality. I would not be shock to see mobsters pass the belt among each other for the chance to live forever.