I think for some people, not having a stash to use expands their creativity.
They are free to plan a project and not have a stash holding them back, because they can purchase just what they want for the project.
I personally do not thrive on making lots of identical blocks for a quilt. I work in a more scrappy fashion and I'm pushing myself to trust my design sense and work more intuitively.
I took a quilting class from a national award winner who said she had given away her entire stash.
I think for some it means leaving the old and the past behind and giving yourself the permission to start fresh with nothing stiffeling or limiting, well maybe just your budget.