Women can wear pants and we can't wear dresses is one of the mantras we see from crossdressers on a regular basis. Let's say that a new fashion trend gained popularity and men actually could wear dresses and skirts as normal daily or evening wear. Designers would come up with styles that matched men's bodies with our flat chests and differently shaped hips and bottom.
Would you wear these fashions and get rid of your bras and breastforms? Would you toss your panties, hip pads and corsets or cinchers and fill your closet with guy skirts or would you continue wearing the more feminine styles associated with womens wear?
I'd probably try to do a little of both, hoping that the new styles would make what I'm already doing more acceptable.