If I may quickly jump in – You touched on this twice, but this paragraph:

When “We Wear Bras” ….it is due to a desire to fulfill a need whether the person is male or female. Just as we desire to wear perfume, jewelry, color our hair, wearing a bra fulfills a need. When women tend to laugh or don’t understand why a guy wears a bra, they revert to a conditioning society has trained them to understand. It was the same way, back in the Victorian days, when women started to wear pants. It was chastised and ridiculed. Today, women wearing men’s styles are the norm

Coupled with this:

boy’s developing because of gynecomastia, women needing contouring and support, men who love the support and hugs a bra provides and those whos testosterone levels and old age has demanded they wear a bra to alleviate pain or provide for their own support.

I believe that’s why women (believed to be more submissive and more prone to social shaming effects) would continue to wear pants, as in first excerpt: practicality. Riding horses and bicycles (date at least back to 1817) make the “pants” far too practical to ignore. Dresses and petticoats would be impossible to keep free of chains and sprockets, and uncomfortable in inconvenient on a horse; side saddle is a recipe for disaster if the horse rears or bucks. Plus, women already wore pettipants (Not sure of spelling) – so the idea was certainly there anyway. Practicality mandated some concessions, and then you have broader and broader acceptance over time…

Which brings us back to males NEEDING support at a certain point. While it’s more common in “modern” times (after 1950s, as food and lifestyles changed, but acknowledging many heavy men existed before this), it’s still seen as emasculating. I understand why – much of masculinity is formed around being physically and mentally “strong,” and needing support is seen as weak – pretty much in the definition. Now, coupled with the reduction in male spaces, there’s less and less “moral support” for the guys, while at the same time, the physical strength is much more a LUXURY (like the Victorian corsets and skirts and such, a province of the upper classes more than the average Joe and Jane) – how much on supplements? How much time in the gym? How much time required by the job, the family, the house? Income vs DIY savings? Etc. We see men being weakened from two angles, the physical causing a reduction in the mental. I.E., being less able to lift heavy things and move them around, plus less need to pick things up and move them around, plus it’s a COST to maintain that physique – now the mental is being battered, and then the breasts grow from a variety of chemical and hormonal means…

I’d guess it’s really only a matter of time before men MUST adopt a bra-wearing standard of dress.

But the funniest part – I’d STILL expect they’ll be divided as you point out, with the “Bro” (Seinfeld) marketed to men – supportive but utilitarian, vs the Bra, still more feminine styles of supportive but also sexy. 😉 Thought I’d HOPE that the cut is different, since masculine rib cage has different shape.

Need to maintain those boundaries!  😉

It will be interesting to see what happens first, as we are in something of a Fourth Turning. These tendencies are born of necessity; Fourth Turning times make the whole world change rapidly and in unexpected ways. (E.G., what will be the long term effects of the sudden MASSIVE spike in “gene therapy” approaches to medicine? And what will the truly fearful Conservative side – used in the US meaning – do, which is often counter-productive to even their actual goal? I’ll never ask “how bad can it get?” because we’ve got millennia of history that shows us. But the “PROGRESS!!!” crowd is no better, it’s a toddler playing with an Explosive New Shiny – when your only tool is a hammer…? OY!) LOL 

Fun times! Lots will happen.