There are multiple explanations, like the whims of contemporary fashion, and this is evidenced in historical artifacts. From the sixteenth to the nineteenth century well-to-do men wore stockings, or "hose". And in antiquity, of course, men and women wore tunics, cloaks, and togas appropriate to their social rank. At present, also, it is important to note that Muslim women ARE NOT permitted to dress like men. If a man were to dissimulate and "dress like a woman", it could be interpreted a variety of different ways, but the mere fact that someone intends to be something they by nature are not is offensive to most people of even moderate intelligence. Because of the obvious natural proportional differences between the genders, it follows that the real natural function of a piece of clothing is that it "fits". And depending on the skill of the clothier, tailor, ect., any piece of clothing can be "made to fit" a particular individual. But this is not profitable for mass-manufacturers, just as people with dwarfism have extremely limited options in finding an automobile that "fits".
