@Batman, The thing is , in the states , the crowds don't come together in their droves for domestic or top fights. It's a culturally different thing. yes, there have been some Stadium fights, but few and far between. Usually with an "Immigrant" fanbase , (Mexican , Puerto Rican) . But for the Major part , the money for the big fights is generated by the TV companies (Like the UK) but Atlantic City or Vegas etc. more than the volume of fans.
This is just my opinion , but it would be better if somebody Stateside could either confirm or shoot down this theory.