Azzaro (and anyone else, of course) here is a pretty good article to ponder in studying the uniquely fucked-up marriage (and non direct-pay sex) scene in the USA.
http://www.theatlantic.com/magazine/archive/2011/11/all-the-single-ladies/308654/?single_page=true
The takeaway I get is that women always want to marry up. Personally I blame the fantasy-world created by the entertainment industry for this, but the author gives no opinion as to why this is the case.
In order to marry up, as women have begun to outnumber men in terms of receiving a college education, and as women now earn significant salaries, a very large number of women now pursue the decreasing percentage of men who out earn them and can carry on a conversation involving the useless shit a person learns in college (particularly the arts and social sciences majors that interest so many women).
This decreasing percentage of "desireable" men reacts exactly the way economics and our knowledge of male behavior would tell us. Many of these guys fuck a lot of women without marrying any of them. It is actually evidence that the USA is not a particularly Puritanical nation that the female examples in this article fuck so many guys. Although strangely enough it was the evangelical religious folk who first warned that society would become a mess if women started becoming highly educated and entering the full-time workplace in large numbers (instead of focusing on spousal and motherhood duties). Perhaps those Puritans, who I hate, are smarter than I give them credit for.
The result of this dynamic the article author describes is that an increasing percentage of American men who do not fit the college-educated, high-earning profile are left significantly under sexed, and a large percentage of the group of women recreationally fucking the small number of guys fitting their desired mold do not get happily married and end up becoming middle-aged man-haters who take their frustrations out by working for groups like End Demand.
Another thought-provoking aspect of the article is that as women have become more promiscuous, they simply seek out and essentially gang-bang (one at a time) the most desirable guys. Hell, so do men, but the existence of female prostitutes means that a guy can do that from age 18 until he is dead. But there is no significant gigilo market - women can only do this for so long and they are bound to be pissed when it ends for them.
Like all articles, it is rather simplistic and ignores a major roadblock to relationships - the significant education and long work hours required to make money in most professions. When both men and women do this, and often geographically move to where the jobs are, the possibilities for successful relationships are lessened.
Once again, I think you are correct that the USA is a pretty fucked up place, but your stereotypes are not the reason. If you are able to figure out the reasons well enough to scam people using websites, I will congratulate you.