I understand that modern outer layers are more functional. A leather jacket, for example, can be dressed up or down so as to be worn in a variety of situations. It is also better at keeping you warm.
However, I think capes/cloaks are more aesthetically pleasing garments. It also feels good to have the fabric flowing around you as you walk. But what do you think?
The actual reason that we don’t is pretty much because of the invention of sewing machines. Once sewing machines were widespread, making coats became sooo much cheaper than they had been. Coats need a lot of tightly made seams which took time and so made coats very expensive. With sewing machines, making these seams was vastly quicker and more reliable.
Coats win over cloaks in so many ways because you can do things with your arms without exposing them or your torso to the rain and cold: impossible with a cloak.
Capes were the short versions - and intended to cover the shoulder and back without seams that might let the rain in, but with the new machine made seams, they were not needed either.
The really big change was when it became affordable to outfit armies with coats instead of cloaks or capes. At that point all the caché and prestige that was associated with military rank disappeared from cloaks and capes and they were suddenly neither useful not fashionable.
Nowadays, of course, they are no longer what your unfashionable dad would have worn: they are quite old enough to have regained a certain style.
I know someone who wears a cloak cape. They explained this to me how practical it was back 300 years ago that you could wear your nightly blanket.
I asked them if that was a situation they ran into often while living in Brooklyn. Having to bed down for the night with your cloak.
Or just living in New York where it’s cold in the winter. It’s a blanket you wear over your coat. You’re not supposed to wear it as your only piece of outer clothing.