... had the latest 'primes' (flourished the most towards the tailend of their careers)?: I've got to say that Lennox Lewis would be up there with a shout regarding longevity. Although his absolute prime is hard to nail down (a testament to immense consistency), Lewis looked as good and sharp as as he ever did from '98 through to '01-ish (First Rahman fight appart) despite having turned pro in '89. A full decade and more onwards. What about Jersey Joe Walcott, who began his career in the early 30's, yet put up some of his career defining performances/victories of his career nearly two decades later. Archie Moore and Bob Fitzsimmons are others well worth mentioning in this regard. Any others you can think of?
Not Hopkins. Nobody mention him please. He declined more slowly than most, but he was far from his prime when he beat Trinidad.
Foreman was far from being the same fighter but some of his attributes permitted him to be competititve even in his 40's. His chin, range, strenght, punching power matched with his thudding jab and new found patience made him a threat in the HW division.
I'm not sure if Lennox got better into the late 90s, honestly. I think it had more to do with his level of competition falling. His most dangerous opponent from 1998-2001 was, in all honesty, Tua. Tua's style + build made him an easy opponent for Lewis to blungeon with the jab for 12 rounds. He also got KTFO in this period by Rahman. Don't even try to tell me that 2001 Tyson or 1999 Holyfield was a serious threat to Lewis, either atsch Lewis' career is interesting...his best wins IMO were Ruddock and Klitschko (and maybe Bruno). He fought ALOT of guys that were either too old and/or shot, highly overrated, or stylistically at a huge disadvantage...but then again, who didn't?