This is an interesting question, because as video games and manga have an increasing influence on comics, the costumes are actually getting MORE complicated and less functional to a real life person.
I have to say, I am fine with comics having a fantasy element, particularly in the costumes. I am not exactly small-chested myself, and some outfits go way too far, but I don’t know that I can expect some woman wearing armor to be thinking of sensible support, you know?
At some point, what we do contains a fantasy element. I think the key is diversity. If we have SOME characters wearing billion dollar armor, it’s fine with me, as long as there are also characters like Misfit who picked her outfit out at the local Goodwill.
EDITED because a poster below seemed to think I was blaming Manga for the large chest sizes of superheroines. That’s not what I was talking about, I was saying the manga influence has made superhero costumes a lot more complex-looking.