In my experience, the more well-off children tend to wear the most used uniforms, they genuinely don't care and neither do their parents. It may be that they don't have to be careful because their parents can easily afford replacements ,so it doesn't matter what they do with them - to a point.
Yes, in non-uniforms school, the unwritten uniform seemed to have been jeans and t=shirt. Not much to the outsider, but the kids knew very well which was the right label, and which wasn't!
In uniform school, you can get away with 5 tops, 2 pairs of shoes. In non-uniform school, you can't turn up wearing the same things every day for a year!
It's not just the money, it's the right style, right fit. Non uniform schools are genuinely awful in term of integration and bullying. It's great if you are in the right group, it s' very lonely if you are not.
It is true that around here the nicer uniforms are from private schools, the state schools ones do look cheap and not very attractive, but they are very cheap to buy,