The degree to which taxes are progressive doesn't determine the total tax collected, or the amount the government expends, it determines how that burden is applied to people. What we should really be comparing is: does an individual allocate their first $100,000 of income with any different efficiency than their second, third, or fifteenth $100k of income? If you give $1000 to a person who makes $50,000 a year, and $1000 to someone who makes $1,000,000 a year, who will allocate that money better? I think most of us would feel intuitively that the person making $50,000 would use it "better", but there's fair arguments to the contrary as well (including figuring out what "better" means). But only when you ask that question are you asking about progressive taxation, not just tax burden as a whole.