Lycra in men's underwear

[JamesSwim]

I posted a similar thread in the Swimsuit board, but thought I'll bring it up here.

Although lycra swimming briefs have been less popular in recent years, I've noticed that men's underwear made with lycra (woven with cotton, polyester, modal or nylon) seems to still widely available. I think men's underwear used to be mostly cotton. But maybe I'm wrong, so wondered if anyone remembers:

When men's brief-style (speedo-type) swimwear was popular years ago, were brief or bikini underwear with stretch (like lycra) was also popular?

It seems odd that brief swimwear is less popular now, but similarly made underwear is still popular.

One theory I have is that synthetic fabrics in underwear has gotten better, so they wick away moisture. Maybe the nylon/lycra underwear in the past didn't keep you dry (didn't matter for swimming but underwear needs to keep dry).

When one goes into a department store's underwear section, lycra based underwear seem to be sold widely, unlike those in men's swimsuit section.