I'm not familiar with US unions generally or the ones you bring p, but if they get unreasonable concessions then their situation may be a type of survivor bias.

I'm not familiar with US unions generally or the ones you bring p, but if they get unreasonable concessions then their situation may be a type of survivor bias. The only unions that are left are the very tough ones? In countries where labour is generally covered by collective bargaining frameworks and enjoys public support, there's a lot of consensus seeking about the unionization ground rules between job market players (labour unions, employer unions, legislature).