What is the fastest way to become a billionaire?

I already know that I need to start an Inc. 500 company. So perhaps the question can be re-formulated as: “How do I speed up the growth of my Inc. 500 company?” Is Silicon Valley really the best place when there is no loyalty there and good people jump ship so quickly? Facebook founder Mark Zuckerberg misses Boston for this reason. Is taking the company public absolutely necessary? Don’t some billionaires keep their companies private and not risk being ousted like Steve Jobs once underwent at Apple? Is the re-formulation of the question really helpful? Or is there another faster way to the top?