Reaganomics is simply neoliberalism ... a belief that markets are the most efficient means for allocated benefits, or growth or whatever term you want to use for "good stuff" in a society. Cutting taxes on the most wealthy by 60%, at a time when rates had been 90% and were still 70% to 28%. The result during Reagan's terms was more income inequality, but at the same time the top 10% actually paid more in an overall share of fed income tax and the bottom 50% paid less .... ALTHOUGH payroll taxes at least partially offset any benefit to lower income workers. (which btw is why mainstreet gopers have little problem with the eitc)
Basically, it freed up capital from tax dodges to seek the best return with little consideration of tax consequences. It coincided with the initial concrete growth from the tech revolution.
There's absolutely no evidence that further cuts created any additional real growth, and give the BushI hikes and Clinton hikes compared to W's cuts, the historical evidence is to the contrary.
However, there's no evidence that a return to classical Keynesian econ would provide any benefit, either.