Question about a fighters "prime" / "past his best"

[ICB]

Does AGE determine whether or not a fighter is "past his best?"

Age of the current Ring P4P 10
1. Pacquiao (29) 2 weeks from 30
2. Marquez (35)
3. Calzaghe (36)
4. Hopkins (43)
5. Vazquez (30)
6. Margarito (30)
7. RMarquez (33)
8. Cotto (27)
9. Calderon (33)
10. Hatton (30)

These are the 10 BEST fighters in the WORLD (according to The Ring). Only Cotto is in his 20s.

Surely ANY win against a fighter rated TOP 10 in the world CAN NOT be downplayed, right? Yet fans/writers make excuses for fighters losses, because of old AGE, all the time.

Isn't this a contradiction?

Thoughts?

No it doesn't it all depends on how many fights they've had, the amount of tough fights they've had. The shape they've kept themselves in. Moving up in a weightclass or moving down in a weightclass, loads of things come into it.