i agree that mileage is somewhat of an issue, but i think it is related to eating/body image issues. i think if more woman were running to be as fast as possible as opposed to as thin as possible, there would be alot more success. mileage is important but more important is the number of years spent running that mileage and i think it is difficult for women due to eating issues/injuries and life/body changes to maintain the consistency in mileage that men are able to.
i also think that the team atmosphere is ideal for many females and it is difficult to recreate that postcollegiately. woman tend to thrive off competition with other woman. i was on a top 5 D-I cross country team and we were all best friends but we also pushed each other to way beyond what we should have been doing. the downside to this is we pushed each other so much that many of us stopped competing at a high level a couple of years after college.
in regards to prize money etc. i wish more college coaches would encourage all their 35-37 minute 10K runners to start thinking about the marathon ASAP. there is a lot of money for not necessarily fast marathon women out there. if a woman can run 2:50 she can easily win an extra $5-7,000 a year picking the right races. obviously that is not enough to solely run but it is enough to keep training and hopefully get faster.