The larger a business grows, the more people become involved in the cooperative, and the harder it becomes to gain consensus or propose more risky but sometimes critical actions for the business.
Layoffs are most probably off the table, while things like employee benefits will probably become disproportionately popular and hard to cut. Furthermore the whole "own your company" appeal seems to become less of a big deal as more and more join the coop, and you get less of a say over how the company should be run. But conversely it is usually on a large scale that the financial benefits of minority shares ownership can yield decent returns. Seems a bit conflicting.
I've heard some groceries in US converted to co-op model though. Wonder how they are doing now.