In the middle of Carly Fiorina's attack on "crony capitalism" tonight, she brought up a real and troubling problem with the economy. Big, older, corporations are becoming a larger and larger part of the economy, while small businesses and entrepreneurship are on the decline.

Here's a chart from a 2014 Brookings paper:

This has been the trend for the past three decades now, and economists still don't have any strong theories. Why aren't people starting new businesses? And why do bigger businesses seem to enjoy such an advantage in the modern economy?

Daron Acemoglu, an economist at MIT, believes that the rise of lobbying is one factor. "It’s becoming more and more difficult to run a successful business in the United States without doing lobbying, campaign contributions and other deals with politicians," he told The New York Times in April.

Carly was likely referring to the bailouts that the banks and automakers received during the recession, but the other form of crony capitalism happens all the time, when politicians accept money and lend their ears to corporate donors.