Well I am both a quilter and fabric collector.
Actually I do use a lot of stash. That is how I plan my quilt. I get stash out and plan and shop from my stash. It is one of the aspects I like the most about making a quilt. It does dictate quilt pattern choice etc. but that seems to be part of the challenge I enjoy.
Most of my quilts are all stash except for the backing and some times the border.
I think it all depends on what type of quilts you make. I make mostly scrap quilts.