> Look at the traditional clothing from almost any part of the world and it was gorgeous and colorful.

Was it?

There's a lot of survivorship bias in old things; we don't see the things which weren't recorded. Old things had their style, that much is unavoidable, but before mass production normal people inherited their clothes because it was just that hard to create.

Also, a lot of the pigments we take for granted today didn't exist at any price in the pre-industrial era, and some which did involved trekking to a mine in Afghanistan: https://en.wikipedia.org/wiki/Ultramarine

This also means (in general, not specifically clothing) a lot of "traditional" things are post-industrial recreations or re-imaginings of the past.

Before the stitching machine arrived in my village, all you can see was large rectangular pieces of cloths, delivered directly from the weaver craftsmen of the village, for men and women alike (only color difference - white for men and mostly dark green for women). The washermen still delivered clothes correctly across dozen's of families everyday, after washing. The famous Indian Saree is an example of unstitched clothing. Dhoti, lungi, turban and towel are other forms rectangular clothing.

People had cultivated an art in how the rectangular cloths are wrapped around them and they clothes are secured at their waist, or around their head. Talk to a Sikh or Afghan about turban.

It was gorgeous and colourful, but highly impersonal. Traditional clothing, almost by definition, isn't really an enabler of personal style and expression. And you can't really compare traditional clothing to day-to-day clothing, these are entirely different purposes and codes.

Day-to-day clothing is definitely not "all just tshirts" nowadays, even in the mainstream. Women fashion is very varied, and while men's fashion is a lot poorer there's still a huge spectrum of expressive clothing that's available. I don't think personal style and expression has ever been as available and encouraged as it is today.