@stevent I didn't mean to imply that people don't care about textile quality, but rather than there isn't the same preoccupation with how substantial textiles are. If Fashion House X produced a heavy wool blazer and a thin super 150s wool blazer, the thick wool wouldn't be considered better quality just because it's thicker. Switch "leather" for "wool" and you'll see that very judgment being passed.
@Distorbiant I think the value of leather in a fashion context is that, unlike most other materials, it carries some cultural connotations (rebellious, luxurious, "edgy", etc). With leather, you're not just paying for the material, but its implications as well.