When two kids from Cleveland invented Superman, in 1938, they clothed him in tights, boots, and a cape. The archetypal superhero costume, on which all others would be modeled, was based on gear worn by circus strongmen and wrestlers: simple costumes of cloth, cut tight to show that the hero was simultaneously a perfect specimen and yet, merely flesh — of us, if not one of us.

Now, “Batman v Superman’’ offers audiences a very different superheroic style. Ben Affleck’s Batman is cocooned in what looks like a diving rig, while Henry Cavill’s Superman, despite being naturally bulletproof, is nonetheless wearing some kind of alien kevlar. What happened?

For decades, audiences were content to root for superheroes wearing brightly colored long johns. When things got weird, it was in the name of realism. In his 1989 film, director Tim Burton wanted to throw off the mantle of camp Batman had acquired in the 1960s. His solution was to encase Michael Keaton in molded-rubber armor that looks like it could at least turn away a knife. (Of course, after Burton left the franchise, it wasn’t hard for Joel Schumacher to steer that armor right back into camp by adding a pair of sculpted nipples.)

Nonetheless, the innovation of armor began a kind of arms race in superhero costumes. They became more and more bulky, more covered in what designers refer to as “greebling’’ — unnecessary texturing that makes an object look more complex (think the surface of the Death Star). Audiences acclimated. By the time the second season of “Daredevil’’ premiered last week on Netflix, it seemed foolish for him to rumble in anything less than full body padding — even though it covers up Charlie Cox’s remarkable abs, and even though the ninjas he’s fighting seem to do just fine in a simple cotton gi.

Even Superman can’t swoop around in anything as simple as spandex anymore. Director Zack Snyder has him in an outfit with the texture of the bottom of a bath mat. It’s a shame. For superheroes, realism eventually has diminishing returns; we’re watching myths, not men. As superhero costumes have gained in greebles, we’ve lost our capacity to suspend disbelief and forgotten what those Cleveland kids taught us long ago — all you need is a cape if you want to believe a man can fly.

S.I. Rosenbaum can be reached at si@arrr.net