Recently I saw a boy who was dressed in girls clothes. The mother said that the clothes had been worn by her first child and since they were new and worn only when the kid was home, there was no point in having them sitting idle around The House. I'm sure she had a good point but the best way to avoid incurring extra costs if you intend to have more than one kid is by buying unisex clothes. That way the clothes can be handed down from sister to brother or brother to sister without having to publicly embarrass yourself.
I don't see a strong distinction between men's and women's clothing. Here where I live there are actually quite a few adults who "cross-dress". It's all a matter of preference. I never really pay it that much attention. Although, when I see guys in skirts, I look a little longer, because it just fascinates me.
I see your point, but not everyone plans to have more kids. My daughter is an only child and I bought her the prettiest ,girliest clothes I could find. If I had had more surprise children, I would have been stuck buying boys' clothes. I think the plan of buying unisex clothes is a great idea for people who are planning to have a big family. I stopped after one kid, so it doesn't really affect me.
Boys or men wearing skirts is not common in my country and I don't plan to let my sons wear skirts when they go out too. I don't mean they can't if they really want to, I just won't do that for them. I agree with buying unisex clothes save more money, as my first child is a boy, and all his clothes can be passed down to my second child who is a daughter. I also don't usually buy things that are "gender-specific", so most of the kids' stuff can be shared among all my children, except for dresses/skirts that my girl has.