Greenspun has an even better explanation of this than I do:
The most reliable source of supranormal profits is superior knowledge of one kind of customer (Way #3). Ideally this will be the kind of customer that larger companies are overlooking. The founders of SAP, for example, were employees of IBM Germany for many years and got exposed to the accounting challenges of large manufacturers. When they quit IBM, they were among the best situated programmers in the world to build an accounting system for manufacturing companies. It is not because these guys were the world's best programmers that SAP is today bringing in $10 billion per year in revenue and has a market capitalization of $60 billion. It is because these guys were the best programmers who understood the problems of their customers.