I agree with many that unions have played an important role in the history of labor relations in the US. They still do.
I have nine years of experience in custom residential audio/video. Vendor training and real-world experience with brands like Krell, Sunfire, Adcom, B & K, JM Labs, Revel, B & W, KEF, Martin Logan, Monitor Audio, Velodyne, Runco, Faroudja, DVDO, Kaleidescape, McIntosh, Meridian, Lutron, Crestron, AMX, RTI, URC, Pronto Pro, and Elan. I hold advanced certifications for configuring (I don't call it programming) RTI and URC controls.
I also have limited experience in commercial projects, from restaurants to MDUs.
In a startup company, I was the project manager, as well as the qualifying party for the contractor's license. In an established company, I'm the lead technician, installer, and assistant programmer. I've made up to $34/hr, and I feel lucky to be making $20/hr in this ecomony.
Putting a lot of bumpers on a car is hard work. I don't think anyone can justify $20/hr for that work today. Maybe in 1990, but not now.

My best friend is a field rep for the leading power turbine manufacturer in the US. He's not union. He's making low six figures. He goes on and on about how union electricians, pipefitters, welders, elevator operators, and other union workers are delaying his schedule, to the tune of way more than an hour a day. He spends a lot of his time sitting around on job sites, waiting for these 'professionals', and the waiting amounts to literally more than half of his paid hours. He's told me stories about the substandard work ethics of union employees that surpass anything in this thread so far, but I don't want to retell them from the 3rd person's perspective.

I can see both sides of this story. I think unions have been, and still are, critical to protect the US labor force, but I think they've evolved far past the point of being beneficial to the competitive ability of American corporations. I have no idea what needs to be done to reign them in, but I know that abolishing them would bring us down the level of the worst communist nations on earth. All I can say is they can't continue to survive the way they are.