If you compare the 20s to the 90s, you'll see a big difference in fashion wear. Clothes seem to get lesser, shorter, transparent, etc.. Do you think in a few years females will start casually wearing just undies and bras?
I've already seen some girls wearing just a top and jeans. Heck, during the summer time, it's not uncommon to see gals wearing daisy dukes and just a bra. :P