100 people wishing they made 250k/yr

"In a study for the National Bureau of Economic Research, Boston University economists Laurence J. Kotlikoff and David Rapson have found that our all-in marginal tax rate is 40%"

This includes sales tax, property tax, and income tax. And 40% is probably a conservative estimate for people making over $250 a year. Does anyone really think that the tax rate should be greater than that? Maybe 50% of my money? Why not a majority of my earnings.