I wonder if any company has ever issued a uniform, said you can just wear this, but made it optional.
I'm one of them, but perhaps not for the reason you'd expect. People tend to forget that uniforms offer a form of protection.
When I was in the military, my commanding officer was an extremely competent man, the likes of which I had never seen before and only rarely seen since. One day, I saw him leaving the base in his civilian clothes, and did a double-take. Here was a man in his early 40's dressed like an overgrown teenager: bleach-faded jeans, an oversized branded tee, flat brimmed hat (labels & holographic stickers still attached), etc. To put it bluntly, he looked like a punk. Had he shown up to work in that attire, and given me orders, it would have been an uphill battle for him to earn my respect.
I exercise a lot of caution when judging people's appearance, and I've long understood that each of us also harbors a degree of unconscious judgement. But this episode forced me to come to terms with the sheer magnitude of that unconscious influence, and with the fantasy that we can rid ourselves of it without sacrificing some amount of individuality. I've come to the conclusion that some degree of uniformity--perhaps just a dress code--can serve to facilitate the upward mobility of the disadvantaged. It's not perfect, but I think it's a whole lot better than today's "anything goes" standards.
Perhaps it's not explicitly a uniform per se, but you could build a fashionable psuedo-uniform out of only a few garments relatively cheaply and without getting looks like you mentioned. That kind of fashion isn't for everyone, but neither is the color and fit maximalism that seem to dominate today's outfits.
It was great for a bit! I felt more well dressed, I was always comfortable, and it was incredibly functional.
Now I realize I like fun clothes too much to stick to the uniform always. But it's nice to have it around to fall back on.