Income tax come out of AGI anyway, not gross income. For example, Warren Buffet made $62,855,038 in 2011, and his taxable income (AGI) was only $39,814,784. Buffett said he paid $15,300 in payroll taxes. Even if he had paid %100 tax rate (39million) he still would have made about 23 million. 50% would leave him with about 42 million for the year. This would help balance the budget and reduce poverty, build infrastructure, fund research, etc.