The wealth that PG and his friends accumulate through app startups does not come from nowhere. The millions of dollars that make a handful of men rich depends on extracting value out of:

1) Government funding. GPS, the Internet, touch screens and the CPU. All funded by government research where the tax dollars contributed by each and every citizen is the investment capital.

2) Global cheap labour. Miners in Africa (mining litium for batteries for example) and factory workers in china provides the infrastructrue for YC startups to make enormous profits.

3) Open source software. Unpaid labour provides the free tools that a startup need to "grow fast" without much investments.

Most people involved in 1-3 don't see any return on their investments. Something to think about.