Front zip vs back zip

[Caultron]

I think part of it is that skirts, especially pencil skirts, are supposed to hang smooth, and a zipper would break that up. So they put the zipper in the back, where it's least noticible.

Another reason is that years ago only the wealthy could afford fashionable clothes, and they always had servants who helped them get dresses. So wearing clothing you obviously couldn't put on and off yourself became a sign of wealth.