To be honest, it's more the audience's fault than the developers. Take Oblivion for example. The female armours are practicaly the same as the male ones; incredibly unrevealing, armour that would actually work as armour. However, Oblivion having such a large modding community there are countless mods to change them, remove the underwear, give the women thongs, etc. It's practically impossible to find good female clothing mods.
Even when a developer doesn't cave to the virgin boys, people will mod it.