I've often thought that the fashion industry would sell a lot more clothes,if the fashion models looked more like normal women and less like a good meal would kill them, so Miss or Mrs average could relate to them .
Benjiboy - you took the words right out of my mouth.
Designer labels feel they (a) want the clothes to hang the way they were designed and (b) give an aspirational "look" to the clothes. Nevertheless, most women are not stick-thin, tissue-paper eating, narcissistic chain-smokers who have cheek-bones like coat-hangers and resemble a zip if you stand them in profile and ask them to stick their tongue out. Thank goodness.
Apparently, the "average" size of a British woman is 14/16 which, on someone of 5'4" to 5'6" tends to look well-proportioned. The makes of "Dove" skincare products got in bang-on right, IMO when they set up their advertising campaign to include examples of women of most sizes, ages and skin colours.
Being inclusive rather than exclusive does tend to work best in a mass-market, though.