Mr. T wrote "is the purpose of a union to help equalize wealth?"
Not really. The purpose of labor unions in the 1940's, 50's, & early 60's was to get a good, sound, living wage for those under union protection, to offer the benefits (medical coverage and a pension) commensurate with that lifesyle, and to insure decent working conditions.
"Equalization" isn't possible or desirable. In the process of accomplishing the above, unions of the 1940's & 50's did somewhat make incomes not anywhere near equal, but less unequal.
I know where you're going with this, Mr. T, so in anticipation of what you've probably already said, What we have today in America is a class of people so rich they've bought the gov't.
They're a plutocratic oligarchy, or as George Carlin put it, "The assholes who run things."
"It's a big club" Carlin said, "And you ain't in it.