Christy is the Mary Richards of this show! Tammy and Bonnie are (literally) head and shoulders above the others. (And as a six-footer myself, I love seeing two tall women on my TV!)
As I understand it, at least here in NY State, you need an AA degree at the minimum to be a counselor for addicts. If they wanted to explore it, Marjorie could certainly do that. (We don't know if she has a college degree or not; presumably she graduated high school).
And that might even be endgame for Bonnie: she could take the GED and go to community college, like Christy did. (For that matter, so could any of the others; Wendy could become a nurse practitioner who specializes in addiction, and Jill (with her a Masters in Art History) could run a non-profit for addicts. (They seemed to be toying with that idea when she cleaned out her closet.
Not that I WANT to see endgame any time soon!