Most folks who lament income inequality have the following model in their head: Wealth comes at a fixed rate from a fountain in the desert, and the rich are the piggy ones who hog all the output of the fountain and won't let anyone else in close to drink. The more anyone takes from the fountain, the less that is available for everyone else. And this was probably a pretty good model for considering pre-capitalist societies. The actual robber barons, before the term was abused to describe successful industrialists of the 19th century, were petty nobles (ie the government of the time) who did absolutely nothing useful except prey on those around them and on those who passed by conducting rudimentary commerce, taking from them by force. That is not how most people become wealthy today, with the exception of a few beneficiaries of cronyism (e.g. Terry McAuliffe).
These issues are dealt with quite clearly from a surprising source -- this review by an economist of the movie "Elysium". I don't really get the schtick at the end with the Adam Smith cameo, but the rest is quite good
Postscript: A while back I was reading the Devil's Candy (terrific book) and thinking about movie-making. Perhaps it is not surprising that wealthy movie stars think in zero-sum terms. I suppose much of their success can be thought of as zero-sum. If I get the part, someone else does not. If I get an extra point of the gross, that is less for everyone else. If this movie does well, that probably means less revenue for another movie that came out the same weekend. Particularly for actors trying to make it or on the rise, movies have a fixed sum of value and they are trying to grab a larger share of that value.
It is interesting that in their own sphere of influence, I never hear about such folks seeking any sort of income redistribution. Perhaps I have missed it, but I never hear Matt Damon say "hey, take one of my gross points and split it up among all the craft folks on the movie, or share it out with the 20 guys who didn't land my part."