Labor union activity is not responsible for the increase in living standards among American workers, who surpassed European workers in living standards at a time when European workers were far more heavily unionized. To the contrary, it was capital accumulation, which made possible greater production and therefore goods whose prices fell relative to wages, that made possible the miracles we observe today. Without capital accumulation, there would have been no wealth to satisfy union demands even if monopolistic labor agencies were a good idea.

I explain this point further in my 33 Questions About American History You’re Not Supposed to Ask, as well as in this video: