Good question. If I’m being honest I haven’t sat down and thoroughly thought about it.
One of the main contradictions I’ve found inside (worker) co-ops in a Capitalist society is that they need to remain profitable and balance worker compensation/benefits/working conditions. As was pointed out in another thread from a while ago, this means that they need to either be quite niche or need to charge higher prices than the corporate competitors.
For me and my experience in my co-op (which is successful, but niche); these conditions lend themselves to focusing on sustaining the co-operative first and looking after the workers there. This means distributing surplus effectively in terms of reinvestment into the co-op and also compensating workers via staff benefits, higher salaries, or flexible working conditions. All of this can take energy via decision-making, and co-opreatives are also a little more fragile due to this compared to their competitors generally being able to offer cheaper services with more infrastructure behind them.
For these reasons, worker co-operatives will generally have a harder time expanding the scope of their benefits outside of their direct membership (and their families). Workers can use the increased flexibility and better working conditions and more stable salary to reinvest their energy elsewhere such as in Parties etc, with the logic being that if you’re not actively fighting against a hostile workspace you might have more energy for the wider struggle. In terms of the co-operative itself, its members can absolutely vote/decide to support and benefit other aspects of the workers’ movements. This can be through financial support, doing pro-bono or reduced-rate work for specific clients (e.g. a co-operative web design agency giving a reduced rate to a Trade Union for designing their website etc), supporting strikes either on the pickets or financially (or even just allowing members to take some discrete time off for these activities if that’s more appropriate to the situation), etc.
However, as noted, the co-op itself needs to be sustainable financially (and democratically; a lot of co-ops can tear apart due to poor democracy and decision-making processes) and ensure that members continue to want to work for the co-op (despite being niche and successful, our salaries are a lot less than our contemporaries in the mega-corp consultancies because we charge our clients less than them). If those challenges can be managed, I don’t see why a willing and politically-aware co-op can’t benefit workers outside of its immediate membership, but these conditions and concerns mean that I’ve found a worker co-op will generally look after its own first. I don’t think this is a bad thing inherently, but I do think that we can’t rely on worker co-ops as a major tool of the class struggle in the long term.
If you find any good literature around how Worker co-ops can fit into a broader class struggle please let me know! All of my analysis is based on first-hand experience of working in a worker co-op since 2018 and being involved with my local Communist Party since 2017, which is likely only a piece of the wider puzzle since all co-ops are different and the material conditions of each country are different as well.
I’m very keen to learn if there are explicit strategies around better utilising co-operatives in class struggle and if there are tools/techniques for avoiding the pitfalls I’ve described.