There's a joke about obesity in America here somewhere... :)

Really, I don't know why weight vs. length. In Japan it's all about length. They rate the catch by the number of centimeters. Weight is secondary.

If length were the deal, I think Florida would be way up there in terms of fish size. Pure Florida strain type bass tend to be very long, especially those minnow eaters you always see in Bassmaster from Stick Marsh and Toho. There's only a few lakes in CA that have super duper long bass. Most err on the side of fat.