They can retrain and join my megacorp if they want reducing the supply for their job and increasing it for mine which should theoretically reduce the pay gap.
Ever since meeting him, I'm automatically skeptical that most people are just reciting platitudes without much real belief behind it.
I don't see the immaturity angle. I think lots of folks become envious and it creates hostility, but envy shouldn't be written off as immaturity.
In some cultures in the USA, money issues are kept private. And even among the cultures where it isn't, individuals may be comfortable sharing it themselves but not with others sharing it, or it being broadcast to the world.
Some spats here or there, and the typical social media outrage, but nothing significant.
Plenty of information out there about who makes how much and it doesn't really matter.
As for the American Dream, it still strikes me as integral the American Dream, I think you just have a different idea of how you wish it was.
EDIT: Also from what I've heard anecdotally, Americans are actually more open about money than most other countries, especially Scandinavian ones.