The power of unions is not just negotiating on behalf of a large group of employees. Imagine if instead of forming a union, the employees formed a worker's coop

The power of unions is not just negotiating on behalf of a large group of employees. Imagine if instead of forming a union, the employees formed a worker's cooperative to contract out their labour. The two companies could then negotiate as equals. However, that cooperative would still not have nearly as much power as unions can have, because it would not be guaranteed an exclusive contract.