I never even thought about the seams/sewing thing, but that completely makes sense.  I've always heard models were thin because they're basically clothes hangers; it's not about the girls, it's about showcasing the shows. And yes, anything that deviates from that body type is going to cost more and be more prohibitive to make.  Fashion is business, of course they're going to maximize profit. I haven't bought pants in years, I'm not sure what size I am now, but last time I tried, 0 was hanging off me.  Thanks vanity sizing catering to whales.