It's a matter of historical fact. When has this not been the case. Can you think of any serious examples? Everyone everywhere all the time is just responding to the incentives in their environment. "Make a lot of money" is a very very powerful incentive.

There are exceptions all over the place where businesses don't act like robber barons, sure. Take for example Market Basket up here in New England, where the CEO for years and years resisted raising prices and tried to treat workers well, in the interest of maintaining a long-term positive image and being a sustainable element of the region's economy. But guess what: he was just forced out for not being greedy enough. Lots of people seem to be expecting a private equity takeover soon.