One issue is with earned versus unearned income. Let's say I have $100 million. I can invest that in municipal bonds and get 1-2% interest tax free on that. If I live on a million a year, I never touch principal (inflation would) and pay no income taxes. Or if I own a company and don't sell it, I pay no income tax because I have no income. If I see part of it, having held it a year, I pay capital gains taxes on the unearned income. I don't pay FICA on any of it.