Your numbers don’t account for tax breaks from then, such as credit card interest. Right now the only deductions that apply to those making over $109k are mortgage interest, vehicle ownership taxes, and charitable contributions. That’s about it. Back then there were loads more tax breaks.
True but tax rates were much higher in the 70s.
As a single guy making good money in the 70s, I was typically in a 40% or higher marginal bracket.