It seems the vast majority of super hero costumes, including the often more "semi-realistic" new ones still tend to carry elements which either date back to the days of the early modern versions, which often took inspiration from circus, athletic or stage performers or the various classic historic inspiration.
Take Superman, the defacto modern super hero, for example. There are elements of acrobts (the striking blue full body suit), strongman and wrestlers (different colored boots and the "underpants on the outside"), swashbuckling adventures (the cape) and medieval knights (the chest insignia).
His prototype design even included laced sandals instead of boots to evoke visual elements of the ancient greek heros like Herakles (compare the original Flash who would take inspiration from Hermes).
Combined these elements, not only on Superman but his various contemporaries including Captain America and Narmor, should have also be seen as ridiculous or silly and yet they not only worked for the audience at the time, but became enduring defacto visual elements of all super heros that followed them.
Meanwhile various attempts at making entirely "modern" or "fully realistic" super hero outfits tend to fall flat, because of not fullfilling the expectation of the viewers, or only manage to stick out when they retain striking visual key elements that don't make them all that different from the costumes anyway (see the Runaways).