I agree, we seem to be adopting a universal androgynous style: jeans, Tshirts, and sneakers.Even so, when we go to the mall, we know who are the girls and who are the boys. The differences are more subtle than the clothes, although stylish fashions certainly do enhance femininity. And masculinity.
I was just making a point about 18th C clothing against the argument of using past male fashions as a justification for saying that men should be able to wear the same thing now. To say that leggings, lace, and ruffles could be considered men's clothing now (I know you didn't say this, but others have) just because they were centuries ago is not a solid argument.
I agree that we all should have the freedom to dress as we please. And if there was a demand for male dresses and skirts, the designers and the fashion industry would be right on it. But, there isn't ... unless you consider male sarongs and kilts that are already a part of some cultures, historically. There have been attempts at getting manskirts off the ground (from several high fashion designers), but I guess they just haven't been popular. Fashions come into popular culture when there is a demand for them. Not the other way around.
I asked the question once and posted links to several manskirt pics, if the CDs here would wear them. Most said, "Ugh, no. Not feminine enough". If you go into the Gallery, most pics are definitely not attempts at portraying a man in a dress.
As to women wanting to wear pants: they did so because they disliked unequal social standards, not because they wanted to present as men. Women wanted to be seen as equals and they wanted the same freedoms that men had. This also meant wearing pants, since wearing dresses restrict the freedom of movement.
And as to the zipper: it is much easier to take the pants off, if they are not made of stretchy material. Women have a lower hip/waist ratio, and this is the biggest difference between male & female jeans. It's a subtle difference, I know, but when you just look at the derrière, you can tell from the back if a person is a she or a he (if he's not wearing hip pads).
Edit - I agree that the more there are positive portrayals of TGs in the media, the more CDing will be understood and hopefully social anxiety about it will diminish. But, I don't think greater understanding will make more males want to wear feminine skirts, if they are not TG to begin with.