The construction unions serve not only to give their members a say, but they generally provide employers with a labor pool certified to be skilled at their task. That function is likely why the construction unions are able to command a premium.
The main thing about unions is that you can ensure and retain quality and professionalism by being able to incentivize competent workers for going to Business School and staying on the floor. I am guessing networks (globalization) and computers (mechanization) have a lot of trades that depend on people staying and doing a good job obsolete. The only jobs that are not in themselves professional and managerial now are service jobs.
The problem with them has been that employers and customers have been tolerant of just low paid service workers doing a half assed job. It would be interesting to see what happens in the next couple of decades. Will they organize and provide a better product that people are willing to pay for? Will they in turn be replaced a new wave of inexpensive robots with enough AI? Will there be no problems with the current status quo of very little asked for and very little given?
You could argue that the reason service jobs are that way is because consumers don't demand any better. Most of the services we "consume" are fleeting, perfunctory encounters. Sure, the cashier at Wal-Mart may be slow and not know where items are and the lines may be long, but people put up with that for 15 minutes so they can pay less for the TV that they'll use hours a day for years. As long as the TV works as it should, there's nothing else to complain about.
I recently did some reorganizing at home and bought a lot of shelving and boxes at The Container Store. The staff were helpful and eager to answer my questions, had a lot of ideas and knew a lot about the products. Because they're relatively well paid, they can afford to buy the products their store sells and can offer advice based on their own experiences with the products. I was really taken aback by how much personal investment and pride they seemed to have in their work. They weren't people who were getting paid $8 an hour, were going to work there a few months and then move on to somewhere else that paid $8 an hour.
But the difference between the Container Store employee and the Wal-Mart employee is also one of expertise. Even if the Wal-Mart employee were paid more, I really don't need advice on buying shampoo and soda. There's nothing complex about that in the way there is about knowing what shelves will fit, what the dimensions are and how well they'll hold up over time and what kind of screws and nails to use to install them.
So, at risk of deviating into Tom Friedman territory, if you want to get paid more than $8 an hour, you need to offer something "extra." There's not a lot of "extra" involved in simply standing at a register, scanning items and swiping the customer's credit card.
