Mayweather's size advantage was too much, period. Marquez' talent isn't anything less than what boxing fans thought; Floyd is just a bigger guy in a bigger division. Marquez needs to stay where he belongs, period.
It reminds me of a sportswriter a few years ago addressing someone who said that the USC Trojans (with Lienert, Bush, etc.) would beat a few of the teams in the NFL at that moment. That USC team was pretty damn great, but if you'd put them against the top team in the NFL (New England) at that time, they would have been horribly embarrassed.
Marquez = one of the best pound for pound boxers in the world. But that jump UP was too much for him.
There's talks about a bout vs. Hatton or Katsidis next...