For all those who are hating on the free-market and greed and selfishness, I advise you to check out Ayn Rand's collection of essays compiled into a book called The Virtue of Selfishness.
The very article you link to carefully distinguishes Rand's definition of selfishness from the common understanding of the word. Rand was herself against the base selfishness that most people are against.
The problem is that pure free markets allow those operating from base selfishness to prosper. You need a credible threat to keep these people in line. Rand perhaps hoped that an Atlas Shrugged style revolt of "prime movers" could provide that threat, but (1) it's much too blunt, (2) relies on Rand's simplistic view that humans are either ethical and productive or looters (which allows her to justify the consequences of that revolt), and (3) has very little chance of actually happening. Which means turning to the state to provide the necessary threat, compromising the cherished ideal of completely free markets. The state may operate imperfectly, and require an ever-vigilant electorate to ensure that it does not overstep its bounds and is constantly improving its methods in accordance with a well-specified set of metrics (which is true of just about any government function), but it's better than letting businesspeople run amok in the name of purity.
Rand's fiction is better than her non-fiction. She makes a good artistic case that selfishness is not a priori evil and is often good. However, if you are looking for rigorous philosophy or social analysis to support such viewpoints, then I would suggest one look elsewhere.
The problem is that pure free markets allow those operating from base selfishness to prosper. You need a credible threat to keep these people in line. Rand perhaps hoped that an Atlas Shrugged style revolt of "prime movers" could provide that threat, but (1) it's much too blunt, (2) relies on Rand's simplistic view that humans are either ethical and productive or looters (which allows her to justify the consequences of that revolt), and (3) has very little chance of actually happening. Which means turning to the state to provide the necessary threat, compromising the cherished ideal of completely free markets. The state may operate imperfectly, and require an ever-vigilant electorate to ensure that it does not overstep its bounds and is constantly improving its methods in accordance with a well-specified set of metrics (which is true of just about any government function), but it's better than letting businesspeople run amok in the name of purity.