/sci/ - Science & Math

i go shopping only rarely (i hate shopping) but i needed new jeans, and to my surprise, probably 95% of mens jeans at stores i went to were something new to me (i heard of them in womens' fashion before but not men's): stretch jeans

so my question is this: is there a scientific reason for why this sort of material is the dominant thing now? what happened to old-fashioned denim? was there some sort of materials-science breakthrough that enabled the stretch material to outperform the 100+ years of denim having the best properties for pants material? or is it some societal thing where now people need stretch more because of, i donno, people's weight fluctuating more lately?

i need some explanation. i would accept that "it's just a fashion trend" but from a fashion point of view, it looks the same basically. so i don't buy that. i have to believe somehow there was a step up in the science underlying stretchy materials that finally filtered through to the market.