You are mistaken. Reagan's tax cuts, which included cuts for the lower class, decreased tax revenue and put more money in the average person's pockets.
Presidents after Reagan started to pillage the lower and middle class for more tax revenue. Notably George H.W. [1]
Taking what you say as accurate and complete just for the sake of argument, those tax cuts also meant that people had a greater non-tax financial burden. They also had adverse social consequences that increased costs for everybody.
The wealthy certainly did get great gains out of it, but it was at the expense of the non-wealthy because the tax cut they received was tiny and didn't offset the increased expenses.
