it was his family that basically made him a champion, it's obvious he doesn't give a **** about proving anything. He just wants the most money and the easiest fight.
He only fought Hatton because he thought he saw an easy fight that would bring in a lot of money, only turns out it was a hard fight for him.
He fought Marquez at welterweight because it was an easy fight that gave him a lot of money, and some weak bragging right that he wooped the guy that gave Pacquiao such a tussle.
Mayweather isn't going to fight Pacquiao because he can make money in other fights and doesn't give a **** about being the best or proving to the fans. As long as he's got that 0, lots of fans will think he'd never lose regardless (even if he almost got his ass knocked out by an old man).
Pacquiao right now is a huge risk for Mayweather, the fight will not happen.