@cwd+17S2yuNB
The purpose of a union is not to protect a skillset. It is to give workers fair treatment and a voice without retaliation.
Your comment “highly skilled people have skills therefore they have choices” is somewhat irrelevant in the non union world when you want to keep your job but there is retaliation. When a highly skilled non union worker retaliates, the worker usually leaves because they know they don't have support when treated unfairly.
There are many non- union workers let into the workplace because of management decision. Many of these workers are then promoted quickly due to who they know regardless of their skillset. You can’t do that in a union.
Also, there are different type of unions (craft unions, technical unions, general unions) There would not be a society of professionals, engineering employees association if your comment were correct because many would have left the union since they are “highly skilled people” as you phrased it.
Retaliation in the workplace is real but being in a union helps shield workers from retaliation. Workers don't have to leave where they want to be anymore due to unfair treatment, they can push back on retaliation/unfair treatment when they are in a union.