My wife studied costume design with a focus on historical European garments a few years back. Fascinating field!

And yes, when you can't mass produce clothing it goes up in price massively. Most mass produced clothing costs slightly more than the fabric, but even a very fast couturier will spend hours on a single piece. On top of that, it's one of those industries where price sensitivity inverts at the upper end.

There was a time not all that long ago that the most expensive thing most people owned was clothing.