Unless you have their balanced checkbook on hand to prove me wrong, I sincerely doubt any mom is spending all the money on herself. Working mothers don't have the freaking time to spend a whole paycheck on themselves, especially with their husbands hiding at the gym, leaving the bulk of the housework and childcare to her. No wonder these women don't want to sleep with your friends.
And yes they are spending all the money on themselves, they can do that, since their husbands cover all the other expenses.
I've been well-aware of the low average quality of American women since college. In high school, I expected them to have horrible tastes in men (pro-meathead jock, anti-smart guy) because that's what the movies told me was "normal" for HS. Actually, HS was not nearly as bad as I'd been led to anticipate. It was the realization that women's tastes didn't improve when I went to an elite college that led me to think something might be rotten in America. A semester abroad confirmed that there really is a difference in the average quality of women, and that the US comes up short.
However, this is an incredibly diverse country, and I live in New York. So, although the average quality might be low, it doesn't need to affect me and, since college, the problem has never prevented me from having a solid dating life in spite of it. Amazing women are definitely out there.