I've read (I think ot was "The Bra Whisperer") that bras are designed to last 6 months, toss 'em after that. I've known a lot of women with whom I'm comfortable enough to discuss these matters (they bring up this exact issue of wire breakout), and not one ever said they followed this even remotely. I can sympathize, as making a several hundred dollar investment twice a year on undergarments seems preposterous. But if the wire broke out, the fabric has worn out, no doubt the elastic is also shot, and the bra is no longer doing more than acting as a nipple cover.
Regarding why nothing better has been designed, my wife and a friend have tried for years now to develop some way to combat underboob sweat at our nudist camp. It's a scourge for them. They've sewn up various fabric contraptions to sling under and around and betwixt and between. They deemed every one a failure. We all just kinda chuckle....engineering is tricky business, and making something functional AND esthetically pleasing (their goal) is a monumental achievement.
I firmly believe that nothing new will emerge until we manage to master levitation....the same guy or lady who develops a compact, fully-contained hoverboard will move right into bras with no underwires, straps or bands....just a pair of comfy cups that lift and separate, maybe give a little teasing jiggle....
That lucky bastard will rule the world....