That's funny, 'cause in my experience, In America, even in California, you mostly get taxed on money you actually make. I mean, mostly; it's complicated. But mostly you pay taxes on the net, not the gross. I mostly don't pay taxes on money I spend on employees and equipment (there are a bunch of exceptions; I pay 7.5% on payroll for employees, and depriciation on capital assets is... well, a matter best left to the accountant. Still.)

And, uh, 50% sure, that's what you pay if you take home a whole lot lot of money and live in California... something that usually doesn't happen during the first years of a startup. In my experience, "starting a business" take home pay rarely gets you much above the 20% tax bracket, even in California; you re-invest the rest.