Okay, so after watching the Summer Olympics I think I have to discount almost all complaints about skimpy superhero costumes, especially for any hero who doesn't need to wear body armor or relies on athletic moves. If you're durable enough to avoid minor abrasions on the job, then it seems the best physical specimens of humanity opt to do their thing wearing less rather than more.

Seriously, could the female athletes where less clothing? The runners on TV right now are in tiny tank tops and bikini bottoms. For some, the numbered tags they have to wear on their chests are larger than their shirts.

Add the crazy colors and designs of athletic apparel, and the use of spandex for about every event in both the summer and winter games, and I'd say that superhero costumes seem pretty damn plausible. Okay, so maybe bustiers are still an unlikely style choice, but still...

... Which is that, ironically enough, the more that superhero comics have tried to tone down their more colorful, absurd or unrealistic aspects, the more that NON-superhero stories in other media have actually ADOPTED those aspects, which basically means that the whole excuse of "mainstream audiences won't accept primary-colored spandex and crazy powers" is bullshit, and really, it's more that a certain subset of PREEXISTING FANS of superhero characters and stories are feeling ashamed of the lack of realism in a genre that they increasingly regard as "immature," but that they nonetheless refuse to outgrow.

The Olympic outfits are only really designed to be used for maybe an hour, and requires maximum performance during that hour. So they're often tailored to the specific needs for the specific event and the specific environment.

In other words, it's hot and humid in Beijing, so the athletes wear as little as possible to avoid exhaustion and dehydration for as long as possible.

Superheroes, on the other hand, have one costume (or maybe several variations or copies of it) that must be used no matter what the environment is like. Cold, hot, rainy, dry, etc. They wouldn't have the choice of changing into one specifically made for the circumstances (except Fashion Accessory, maybe). So they need one, or maybe two if you want to go seasonal, that can be used in all conditions.

That makes most of the "minimal" superhero costumes very impractical. It also makes most things like skirts - or anything else that doesn't stay in place on its own, and might increase self-consciousness - impractical because they'll be a constant maintenance issue.

Again, environmental needs only come into play for characters that are affected by such things. When someone like She-Hulk, Warbird or Wonder Woman can hang out in space, it's hard to believe they're worried about the weather.

My point is that, removed from actual protective needs (many events in the Olympics are in climate controlled environments) most athletes opt to wear less rather than more. I see no reason why that wouldn't carry over to heroes who also don't need to worry about those needs.