When I was very young I worked a tough job that had a mandatory union and it was quite terrible / weak. Working conditions were pretty bad, physical labor, etc. But it was not until I worked a job with no union that I realized every element of that job that didn't suck was due to the union. For example we had supervisors but they didn't follow you around and micromanage you. You were just expected to do your job. If…
Technically, that does not follow. What can be inferred is that companies believe that unions will cost the company money, but this does not necessarily mean that the employees will get any of that money. One could imagine a theoretical evil union which takes all the extracted profit from the company and gives it to themselves, and not to the employees.