NEW YORK (TheStreet) -- It's hard out there for a Carnegie -- or a Gates or a Buffett.
A century ago the great Andrew Carnegie was busy giving away the last of his estimated $10 billion fortune.
Your town probably has a Carnegie library in it. I have a nephew whose band will play at Carnegie Hall soon. Carnegie Mellon University and dozens of other universities owe their lives to his generosity.
But extreme wealth can have a self-sustaining quality to it. It can keep growing, even when you're trying hard to give your wealth away. Carnegie's philanthropy began after he sold his company to become part of U.S. Steel (X) for $480 million in 1901 dollars. He wound up giving away 10 times that much.
That's also the secret behind Bill Gates' return to the top of Forbes' billionaires list.
It's also the secret of Warren Buffett's continuing relevance.
Gates didn't hang around the office much in 2013. Instead he spent most of his time at his Gates Foundation working to end dread diseases, aid developing countries and improve education -- to become a 21st century Carnegie.
Despite this, he managed to take back his title of world's richest person from Mexico's Carlos Slim. (Gates has $76 billion vs. Slim's $72 billion.) American media celebrated like we'd won something.
His was not a case of special genius, however. Gates mainly stayed invested in the stock of the company he co-founded in the 1970s, Microsoft (MSFT). The shares rose over 35% during the year, from the mid-$20s to the mid-$30s, and his fortune increased by $9 billion as a result.
This may be Gates' last appearance at the top of the charts, however. He's moving from the passive role of chairman to a more active role as adviser to incoming CEO Satya Nadella. Last year's gains may prove hard to sustain as the cloud grows, as Microsoft devices continue to struggle and as the PC market continues to shrink.
Buffett, meanwhile, clocked in at number four on the billionaire hit parade, with $58.2 billion.