So someone on twitter asked this and it seemed like a good question Who'd you back out of a say 27 year old Floyd and a 37 year old Floyd? Both quite different styles and great in their own way
PBF at 130lbs was most probably top 10 of all time in terms of head-to-head ability. At around 27 years old, PBF was at 135-140. A 37 year old, welterweight Floyd would be beaten by SRR, SRL, Hearns, Napoles, Duran (prime for prime, all five of them are definitely better than a 130lb Mayweather), Curry and probably Griffith, Rodriguez, Benitez, and 50:50 = De La Hoya, Pacquiao, Forrest.