My school has no (or very limited) uniform. Pupils are supposed to wear black and white with a school hoodie but most don't bother and no one cares. Not sure how, if we were to introduce a traditional uniform, it would prepare them for the world of work, however. Some end up at sea, living in boiler suits, 1 is a TV presenter, several teachers, a few work in shops - just your average school with pupils with all sorts of aspirations. The nurses I see, those in the Co-op, even the lawyers and the doctors I have taught, all seem to manage quite happily to confirm when required.
When they go away to do business competitions, they all take pride in dressing up in suits or business wear (or whatever is required) and they all seem to look far smarter than the usual polyester rubbish schools get pupils to wear.
I am always agog, after 25 years of teaching to hear (and see on TV) pupils being isolated from lessons and given busy work to do because of the wrong hair / socks / piercing.
My job is to teach them about English. Any time spent moaning about socks, or missing a lesson for having blue hair, is time taken away from their education. It is hard enough educating teenagers without ruining a working relationship by having to nag them about what they are wearing.
The movement towards strict uniform gives the superficial appearance of excellence and motivation; it has no proven link with academic achievement and, indeed, often results in less time spent - you know - learning stuff that matters.
I don't want to, or need to, teach hair colour and sock choice when I am so desperately needed to teach reading and writing.