The dilemma with co-ops

I can give you some of my personal experience with food co-ops. When I lived in Tempe AZ there was Gentle Strength co-op, no defunct. One could work there to mitigate the higher cost of its food. As I recall, noting said recall might be inaccurate, If a member worked 2.5 hours per week they'd get a 7% discount. If one committed to working 20 to 32 hours per month there would be 25-30% discount. They lost money on the member discounts but made up for it in non-member sales. When the new kids came to town, like Whole Foods and Trader Joe's, the co-op could no longer attract enough non-member customers, given those prices were lower than the co-ops. Hence they went under.

On the other hand there's La Montanita in Albuquerque. Their prices are well over the market competition like Trader Joe's, and even regular markets like Albertson's or Walmart that have organic or natural foods sections. And yet they remain viable. But how? There are no member discounts is exchange for working to mitigate prices. Hence a significant portion of us on lower budgets for whatever reason simply cannot afford to shop there. The co-op survives on rich college kids from the nearby university, as well as well off Yuppies with a social conscience.
But what of the old hippies that have the social conscience but have chosen not to participate in the capitalistic exchange of work for slave wages? That choose an alternative lifestyle more based on the emerging sharing ethic inherent to the collaborative commons, where one can exchange goods and services for other goods and services? It seems that is also the ethic of co-ops in general. But in dumping that ethic to cater to those who can afford the high prices to keep the co-op viable seems to be defeating its very purpose.