There’s certainly options above temu junk. Maybe it doesn’t meet your bar but I’ve found the 100% cotton stuff from Uniqlo to be massively higher quality than the average. I’ve got tshirts from them I’d guess I’d worn and washed 80+ times.

You can still go to a tailor and commission jackets, trousers and shirts, made with the same quality of fabrics and manufacturing techniques. With shoes, you can still go and buy hand welted shoes.

It all comes at a price but I don't disagree that we have a barbell problem here (ie cheap fast fashion or bespoke, with nothing in the middle).

There absolutely are still rich-people brands that sell absurd quality at absurd price.

See, for example, Marine Layer in San Francisco, or boutiques like Red Ants Pants.