I agree, but the issue is that the union really gains a lot of strength from controlling most/all the workers. If there were 5 equally popular guilds, a disagre

I agree, but the issue is that the union really gains a lot of strength from controlling most/all the workers. If there were 5 equally popular guilds, a disagreement with one means only 20% of your workers stop, which isn't as big a deal as all of them being forced to stop work.