Kind of amazing to see the topic whirl around and around when its quite straightforward about the WHY here.
Crack open probably the majority of older Fantasy art, and the 'issue' becomes obvious.
Why is there a difference between Male/Female armour representation? Because its 'always' been that way. Why is it that way? Talk to folks like Frazetta.
No value judgments here btw, I cant be bothered to get into that, but it is what it is, and there's no way people dont get the underlying reason after 12 pages.