On fashion and racism

Pop quiz: what do Hoity Toity, Photo Finish, Prim Hemline, and Manhattan have in common?

It was a trick question; I actually wanted two answers: fashion and earth ponies. Manehattan is a metropolis with a strong majority of earth ponies, and apparently the most glamorous city in Equestria and the leader in fashion. And fashion is a field strongly dominated by earth ponies. So far as I can tell, Rarity, Fluttershy, and that one pegasus who was carrying Photo Finish in that one scene are the only non-earth ponies we have ever seen involved in fashion in any manner other than as customers. Two of them are main characters, and thus cannot be assumed to be representative, and the third is a fashion photographer's litter slave. Seriously, if he mattered at all, he would at least be carrying a designer. In particular, I would like to reiterate that Hoity Toity, who is at least very influential in the Canterlot fashion world, if not the most important figure thereof, is an earth pony, despite Canterlot being a unicorn city.

So we are left to conclude that fashion is an earth pony's line of work. And we are left to wonder if Rarity will run into trouble from this. Probably not in the show, of course. It would be interesting if we did one day see one of the Mane Six suffering from racism, but I just don't see it happening. But the fact remains that out of the Mane Six, Rarity is the only one with ambitions outside Ponyville that do not strongly align with her race, and so if any of them were to be a victim of racism, it would most likely be her.

Also, how hard is it to find comfortable fancy clothes if you are a pegasus? If all the designers are earth ponies, there can't be that many who really know how to design around wings.