I say this because everyone on the "team" will have competing priorities and either the CoOp clients will suffer or the CoOp product will languish and never get the attention it needs. I can say this from direct experience working with a team that was all "independent" but were taking a draw to work on CoOp projects (we didn't call it a CoOp but that is what it was). We were constantly juggling priorities more so than if those same team members were full time. Making a deadline was nearly impossible because people each had their own competing priorities. Managing client expectations was nearly impossible because you couldn't predict what anyones schedules were, and frankly I don't feel they were being honest with me or really even themselves. Mind you I don't feel any of the people were evil or bad people or I would never have worked with them, but we all have priorities and needs that we will serve first. And if your priority is putting food on the table for the family then you might be more inclined to work for $125/hr with a direct client rather then a CoOp client were you personally might only take in $85/hr (the rest going to support sales & management efforts of the CoOp etc) or where you are working on a product and there is no revenue yet.
CoOps to me are not effective for a development team or as a consulting group. You either have dedication from the group or you don't, and splitting their attention never seems to be effective. The idea that someone will spend 2 weeks out of a month on CoOp work and 2 Weeks on personal Client. Or 2 days a week on CoOp and 3 on Client or whatever split someone tells themselves is only good until the first client call or broken code that needs fixed now. Then stuff just changes.
As for your personal situation, good for you to recognize and be honest with yourself about your abilities. But I have to think with 4 years of experience either you are better than you are saying in which case you are under valued; or you aren't getting larger concepts and need mentoring and/or training. Or maybe development just isn't for you. But no matter which it is, you have to be realistic that joining a CoOp or trying to consult requires solid skills, time management and in general a network that you can use to help get work.