Because the workers are also shareholders, and shareholders like money either way. Some of their business units were becoming extremely uncompetitive. So they ship a bunch of the manufacturing away to subsidiaries where you are not really a member of the coop: You aren't getting shares if you are in many of those other subsidiaries. They still managed to build a class system anyway. If you work at their retailers, you aren't the same as if you work at their Basque factories.

As for workers that were part of the coop in uncompetitive jobs, they moved them around as they could, but ultimately no amount of union or coop-like behavior is going to help if you are getting outcompeted.

A lot of people think it's all wine and roses when you get more worker input, but then you realize quite a few of the warts come straight from having a bunch of people with different amounts of power, and you still have power differentials even if everyone votes.