I tend to think that these arguments get cause and effect backward. Unions were strong in the 1960s and 1970s for the same reasons that inequality was low — and while the law may have been one of those reasons, it was at best a minor reason.
To see what I mean, look at the United Automobile Workers union, which is a pale shadow of its former self. Its workers have made huge concessions, and its numbers have dwindled to the point where the union, like many of the mighty industrial unions of the past, has more retirees than workers.
Is that because the law won’t let them strike? Obviously not; the problem is that striking wouldn’t do them any good, because the companies they work for are too fragile to give them more money. A more labor-friendly National Labor Relations Board couldn’t magically generate the profits and market share necessary to pay hundreds of thousands of workers above-market wages, as General Motors Co. did in the 1960s.
The modern industrial worker’s main problems, which have nothing to do with the law, are: