It started with Regan tax cuts and trickle down voodoo economics.

High corporate taxes incentivized business investment that built the middle class.

Another stupid move was legalizing stock buybacks that was previously considered stock manipulation.

Doesn't even touch that the tax code is purposefully complicated to have zillions of loopholes so the very rich pay little to no taxes while everyone else funds an out-of-control military-industrial complex and socialism for the rich.