Entrepreneurs who take on risk want to keep control of the spoils, imagine that.

A millionaire's tax is the flip side of "privatize profits, socialize risks."

Privatize risk, socialize reward.

If riches were obtained solely by pulling oneself up by their bootstraps, I would wholeheartedly agree with you. However, the behaviors or methods that got that person their riches matters, or should matter, especially if it’s unethical or illegal.

The same entrepreneurs who use public infrastructure, right? Like transportation, utilities and physical systems, internet and telecommunications, the legal system, limited liability, money and banking, capital markets, an educated workforce, nationalized science and R&D, public health, emergency services, commercial standards, trade infrastructure, national security. Let's see, there's also land and property administration, environmental infrastructure, the entire labor ecosystem.

Let's not leave out bankruptcy protection, emergency lending, industry bailouts, disaster assistance, government procurement. Oh, and the Federal Reserve standing behind financial markets to prevent the entire credit system from falling to crap.

I'm pretty sure every entrepreneur took advantage of nearly all of these publicly paid for infrastructure to get where they are, today. There would be no spoils for Brin if not for all these things. Things that taxes provide.