Because every size requires more patterns and complicates fabrication. Even brands that used to have it (Gymboree) stopped, and kids have to be awkwardly swimming in clothes. Same with split sizing (L being 10-12 comes to mind). Brands want to cheap out as much as possible for profit purposes.

My skinny 10yo is swimming in size 10/12 clothes and too tall for size 8. I have found that H&M and Hanna Andersen run big so have been buying size 8 in those. It’s ridiculous

I started buying H&M when my daughter was 9.

Size 9 is M
Size 11 is L

Same!! Also size 11!!

I have always wondered this, even though my 9yo still wears an 8 (very skinny).

It seems like clothing sizes for girls skip size 9, even though they do all the other odd/even numbers. Are there any brands that do size 9?