The problem is not supply side economics— it’s amibtious politicians who then take the extra revenues and spend it foolishly.
The other issue is Wall Street. They no longer want to invest in long term productive assets in the United States. Instead of a place to raise equity capital, Wall Street is a casino where speculators spin the 401K’s and IRA’s of the public, siphoning off huge fees and living their customers and the taxpayers holding the bag when they fail.