Michael Lind is almost always right in his analysis:
Low taxes on rentiers. In the late 20th century, the U.S. and a number of other capitalist countries made tax rates on capital gains lower than tax rates on wage income. This was supposed to encourage investment in productive enterprises, but in fact it merely provided the super-rich with windfall fortunes that have often been used for stock market and real estate speculation. Thanks to privileged tax treatment of capital gains, Warren Buffett complains that he pays lower taxes than his secretary, and Mitt Romney — the poster boy of rentier financial capitalism — paid 13.9 percent in taxes in 2010, lower than the combined employee and employer payroll taxes paid by low-income workers who pay no federal income tax (and not counting the state and local taxes that they pay). America’s rentier plutocracy has deployed campaign contributions to intimidate Congress into keeping taxes extremely low on those who make most of their income from investments, whether the investments enhance the American economy’s productive capacity or not.
Privatizing natural monopolies. The classic productive capitalist wants to found a company to provide a new, socially useful good or service and make money by sales. In contrast, the classic parasitic rentier wants to bribe the state legislature into privatizing and selling state roads so that he or she can make money without effort or innovation every time somebody drives and pays a toll. Not only progressives but mainstream conservatives used to agree that natural monopolies, such as many infrastructure services—water, electricity, transportation — should be either publicly owned or publicly regulated utilities. Today, however, some plutocrats, seeking guaranteed, recurrent streams of money for little or no effort, fund politicians and ideologues who favor privatizing or deregulating infrastructure and public utilities and cutting or voucherizing Social Security and Medicare, to force the elderly to buy financial products and costly health insurance from the rentier sector.
It's all about the greed.
As with parasites in the animal kingdom, they eventually kill off the host and eventually die themselves.
These greedheads, however, have politicians in their hip pocket and an ideology called "neoliberalism" that provides "intellectual" cover for their sociopathic behavior.