Project Censored published a great report that surveys many of the organizations, their boards, and so on. First report whose theory is very similar to my own research.
http://projectcensored.org/the-global-1-exposing-the-transna...
As you can see, the boards have considerable overlap where people who appear to be competing in one sector are working together in another. There's also a clear incentive, per doctrine of maximizing selfish gain, for board members and CEO's to all give each other ridiculously high compensation while driving it down for laborers. The reason: they can. Why else?
So, it's a combination of corrupt politicians, elites at CEO/board level, and media whose boards work similarly. The worst part is that the media is critical to changing the situation but has financial incentive to avoid that ever happening. That's why they so deviously self-censor on these issues to the point Americans can't get mad enough about the specific problem to do something with specific solutions. Media never presents either. Instead, works on side issues or total distractions (esp shootings or celebs) that prevent threats to stability of plutocracy.
EDIT: Given not everyone likes this source, I'd be interested in any similar data and analysis from academics published in a peer-reviewed journal. No paywalls, though. Can't fight elitism with more elitism. ;)