There's also a very simple hydraulic to answer the question that shows the tax leakage. In the 1960s, personal income taxes contributed about 30% of federal government revenues. Today they account for almost half: 47%.
Look at corporate taxes in comparison. They've gone from about 19% of federal government revenues in the sixties to about 13% today. So it's a sea change; there's more reliance on income taxes. It's like taxing capital less and taxing labour more.