Actually: There’s been a noticeable uptick in the last decade+ of better-made clothing for shoppers who are open to paying somewhat higher prices. Not boutique prices, but also more expensive than H&M.

For a long time the stereotypical “young professional” look was tied closely to just a few mainstream retailers (Banana Republic for example), but over the last ~15 years a wider range of smaller or more specialized brands has entered the space: Alex Mill, Spier and Mackay, etc.

But even ignoring that your analogy doesn’t quite fit since price plays a significant role in clothing purchasing decisions: Fast fashion succeeds largely because it is cheap.

If reasonably priced, higher-quality alternatives were accessible people would buy them. It’s partly why certain brands have grown in popularity (Carhartt, for example).