I like your humor.........YES!!
People don't wear capes for the same reason people no longer wear knee breeches or oversized, ruffled sleeves.
They are out of style and come across as costume-y.
Can you wear a cape? Of course. They are typically the domain of eccentric, older men, however.
A younger person doing it would be viewed as "trying too hard" or ridiculous. That's why I imagine people don't do it.
Men don't wear umbrella hats on their head in the summer either though it makes a lot of sense.
If I was an older man maybe I'd wear a cape just for the hell of it as it would undoubtedly get lots of attention.
I personally wouldn't wear one because I think they look ridiculous. It's on par with the Victorian-era crowd, Fedora Lounge dressers, etc. You simply look out of place, and like you're on your way to a carnival, theme party or something.
Other than that, they're pretty much associated with geeks over here.