Either Avis has an awful business model or I'm completely missing something...

I'm looking for a car over thanksgiving (11/27-12/3) from IAH. Hertz, Budget, and Enterprise are $145-$175 with USAA discounts and $30-$35 off weekly rental coupons. Avis? $260 with a $30 off coupon and the USAA discount! How can they get away with that? I guess they do enough corporate business that they don't need to be competitive in the public market? Maybe it's just supply and demand--their rates were so low earlier that they've increased prices due to low supply? who knows! but nonetheless, this is frustrating. I wish my company rented with Hertz or National instead of Avis...