“The truth, however, is rather more complex. One factor at work is economic globalization. Businesses fed up with unions who think that their industry should be immune from competition are now in a position to move their operations elsewhere — ranging from the southern states of America, to China, India, and other developing countries — where people and governments enthusiastically welcome the influx of knowledge, capital, and jobs. In this regard, it’s always struck me as ironic that unions in developed countries regularly act in ways that essentially hamper economic and employment growth in developing nations. So much for the “international solidarity of workers.” Comradeship apparently stops at the Rio Grande.
A second and related factor is the increased mobility of people. They are more willing to go where the work is. This has always been a prominent social-cultural trait in America, but it has visibly accelerated in recent decades. Mobility often means that people change both the character of their work and their employer on a relatively regular basis. This makes it harder for unions to recruit and maintain steady membership. Unions have not adjusted to the fact that the days of people working in the same job in the same industry for most of their lives have been over for some time.”
Read “Unions and the Path to Irrelevancy” by Samuel Gregg on National Review Online.