Once upon a time, forceful personalities like Rockefeller, Ford and Carnegie drove business empires — and their egos drove them. But the business climate has changed drastically in recent years. With rare exceptions, single companies can no longer monopolize a market. Competition has also increased, especially as advancing technology has made start-ups common. Nowadays, just a few talented individuals can overturn an entire industry — just as Steve Wozniak, Steve Jobs and Bill Gates did it…