John, unions and emploers "enjoy" adversarial situations. Unions are necessary to protect all employees from employers who choose to abuse them.

Yesterday, I was aboard a launch service in New York harbor. A few years ago, there was a fight between the unions and employers to maintain workers' rights in the local shipping industry. The unions were locked out and eventually lost. The thoroughly professional crew on board this lighter, many of whom have been working for the company for years, have no benefits except for what they fund themselves. That includes retirement. There are no limits to the hours they are expected to be available. I joined them at 5 AM and left them at 6:30 PM. Would you do demanding physical work out of doors in these conditions? The pay is good but what is your life worth?

As far as the example you cite, you are not presenting the whole picture. The supervisor is also incompetent. If the bad employee's deficiencies are properly documented, the employee can be "non-renewed." This is common to most union contracts and, though appealable and, if the supervisor has done the appropriate work, effective. It's called leadership.

Yes, there are difficulties and expenses. It can be done, though. By the same token, though, both sides' interests should be protected.