I don’t see much benefit of a fork being a member coop, since the product is already free. I could potentially see a worker coop - if this fork was intended to make a profit, and the people working on it are then incentivized to improve the product because they’ll personally benefit, then maybe we’d see more movement and innovation.
The fork is to preserve the core browser experience and provide security updates. If you hate AI jank bloating software, your best options for a browser is Chrome suffering. Certainly, you can refuse updates on Firefox going forward if they commit to this path, but you’re a single missing patch away from being an easier target for bad actors to exploit your security vulnerabilities