Why would any man want to marry an overused woman who might have decided her sleep-around years were over?
I agree there; I wonder how many of these women having problems finding nice men are the ones with almost as many lovers as Lindsay Lohan.
You have a large number of women chasing the same small group of guys they find "desirable". The women get used and dropped (why think of commitment when you have multiple women chasing you? Just move on to the next younger, fresher candidate when the current one makes commitment noises).
The "desirable" guys have fun. The "nice-but-not-rich/handsome/exciting-enough" guys experience lack of success in their 20's, until women hitting 35 decide to "settle". Many men say "no thanks" to accepting a high-mileage woman who will never really be satisfied with him anyway.