At least there is a market rationale for the huge salaries of sports stars and movie stars. Michael Jordan commands large amounts of money because it is damn hard to find anyone else on the planet who can do exactly what he does. Same for Harrison Ford. You can't easily replace these guys and get the same results.

With supply and demand, if the supply quantity = 1, then the price is going to be high.

The dockworkers, on the other hand, could be easily replaced by thousands of other people who could do the same job and would be willing to do it for a lot less. Only the union and its threat of destroying the industry prevents this.

One must admit that there has to be a middle ground somewhere between massive featherbedding and $150,000 a year dockworkers, and slave wages and Pinkertons. Be nice if someone started looking for it.