Hypergamy is a woman's natural desire to trade up. Its the reason why your girlfriend would forget about your three year relationship if Kobe Bryant dropped his trousers. However female hypergamy is also the reason why women are never there at the start and only get involved when things begin looking up.

Personal Computing When Microsoft and Apple first got started the work force was predominantly male. Now Microsoft's workforce is 25% female a massive increase. But why is this? When these tech companies were new they needed very high productivity to stay afloat. Want to work for Apple? Cool, go solder wires in my garage for eight hours, maybe you'll get payed maybe not. Very few women sighned up for this kind of work, because women are risk averse. However once these companies start getting large and profitable they could afford to hire women as front desk staff, marketing, middle managers etc, positions that are necessary for a large company but no where near as necessary as the engineers who actually make the product.

Comic Book Conventions In the 90's Comic Con was pretty much a male nerd convention. Where groups of men and boys would go to meet with the authors and argue about comic book dogma. Comic Books were uncool so there was very little female participation. That all changed. Hollywood realized that instead of taking risks on new screen plays it could just tap into the Super Hero genre. As soon as capital was there, Comic Con became cool and women started showing up in thongs dressed as various characters, claiming to be 'nerds'. Realistically its safe to assume that women are there for the spectacle, attention because women only started showing up when those things became a factor.

Fitness Back in the 60's most gyms were poorly lit dusty rooms filled with rusty weights sweating men, and tons of homosexuals. Golds was a huge gay pick up spot. Bodybuilders were though of as weirdos and were shamed by women to fulfill traditional gender roles. The fitness industry started exploding when men saw Arnold in Conan and wanted his body. Gyms started getting built. Fitness became trendy women started showing up. In fact Fitness is so trendy now that gym membership not attendance is predominantly female (my district manager once told me this). For this reason gyms are getting feminized less squat racks more zumba classes. Women don't understand the irony of being on the elliptical and being repulsed by a large bodybuilder. The bodybuilder belongs in the gym because he uses the gym as a means, the elliptical rider does not, she is there because its trendy to workout.