Because it's based on conjecture and supposition and I'm not bothered enough to watch loads of LW Mosley film or argue about how good or bad he was at the weight.
Mosley was a great fighter and went 9-0 with nine KOs in lightweight title fights. However, none of his opponents in those fights was anywhere near the level of the great fighters mentioned in the OP. The funny, and somewhat sad, thing is that none of them fought an all-time great fighter while they were lightweight champion. That is a lot of potential great title fights we've missed over the years. From a matchup point of view, I don't think Mosley beats Mayweather. He would have given as good as he got against Manny and JMM and he would have been way too big and strong for Loma.
You've been gone for far too long, man. It's not a good sign when Egyptian Gods start whispering in your ear. I mean what's next ? Mickey Walker beats Freddie Steele ?
Saint Primo predicted the outcome, but many warriors were wounded in the Walker - Steele battle. It's an event that lives in our hearts.