I am an avid supporter of Bernie Sanders, but he and all other Progressives must stop complaining about the wealth/income gap as being UNFAIR (it is). (That plays into the "you are jealous” meme espoused by the super rich.) Progressives must, instead, point out the economic harm that wealth concentration at the top causes. A healthy economy must have a high velocity of money circulation and wealth at the top does not circulate. That means we must tax the rich-of-today to fund the youth-of-today's education, health and housing, and, we must tax the rich-of-today to pay for transportation, communication and energy infrastructure for all.
This is wealth distribution for the express purpose of increased productivity. It is a moral economics, and, hopefully, may change who the future rich are--the Jamie Dimons being replaced by boys and girls from Anytown, USA. There is nothing wrong with being rich, as long as that population changes names over time…as long as we have upward mobility readily accessible to the poor youth as well as the rich youth.
(gdn: I have sent a copy of this to Bernie Sanders's website, saying that I have posted this content to both Twitter, FB and my blog)