Personally, I blame the decoupling of the dollar to the gold standard and the distribution of newly minted dollars from the federal reserve into the well connected via banks and corporations that are controlled by a small social segment that all attend the same schools.
Once money became a thing that doesn't cost anything but the changing of zeros, then growth becomes a question not of how to produce something to get money, and but how to get the both the connection and the pedigree needed to receive cheap dollars.
This has created money silos, where the US aristocracy will take hundreds of billions in loses to capture a market and then extract value in monopolistic ways.
You can see this with google, facebook, amazon, etc.
It wasn't always the best companies that won. It was the best companies that had access to the vast capitals pools created out of thin air and who could promise to operate at the monopolistic scales the monied classes were aiming for from the beginning. That is why Ivy leaguers (whether drop outs or not) were chosen as the princelings. They are people who have a lot committed into the system and wouldn't dare betray it: they can be counted on to take things to their logical extreme.
I think also pertinent is the locking out of the middle and lower clases from growth fases of company creation (incentive angel investors and delaying IPOs + legally enforced discrimination against investors based on social class) - Oh and the pooling of legally stolen funds (pensions) into 'safe' stocks. Not to mention the legalization of bribery which has further accelerated our current state of legislative capture.