Is there a good reason there are so few lightweight sweat/lounge pants, at least among non-Asian designers?

I know brands like Julius, TVA, and plenty of others have been doing lounge pants made of breezy materials (ramie, linen, light cottons and polyesters) with narrow hems (whether cuffed, fastened with snaps/drawstrings, or just tapered, sometimes cropped and sometimes not) for a while. And Geller's lounge/flight pants are some of his most popular models. But I look around at Western designers (except for Rick), and all I see is an enormous number of cotton or terry pants...literally "elevated sweatpants."

I've got no interest in the latter and a huge interest in the former. But the former (lightweight pants/trousers with narrow hems) seems to be really difficult to find, unless I'm totally missing something and looking in the wrong places.

Is there something I'm not getting here? Is there just not a market for, you know, pants you might want to wear when it's over 85 degrees out? That's not a rhetorical question...I think I must be not getting something, and that there must be a good reason why these aren't more popular.