Vermont has a fairly successful Co-op in Burlington.
Most food co-ops belong to co-op partnerships and many will cross honor memberships at other co-ops ie the Putney co-op will give you a member discount if you're a Brattleboro co-op member
A co-op has a lot of positive externalities: better customer experience, better benefits, pay, and job satisfaction for the employees than at non-co-op grocery stores, the community it fosters, etc. If these things matter to you, they can outweigh the premium the co-op has to charge to provide them.
I worked in the Lexington Co-op in Buffalo back in the 90s. It was a great job despite the meager pay and benefits (at the time) because I didn't feel like I was the lackey of the customers or my bosses but their friend and neighbor. I was in graduate school, which was depressing and alienating. I found the co-op a far nicer place to live my life than academia. It's been many years, but it's still one of the best jobs I've had. I met my wife there. My pay is better now, but I still shop at co-ops when I can.