The right misquoting LVM or Rand when they understand neither is of no consequence. They have been rationalizing around the ideas they don’t like to cherry pick the one’s they do for decades. Embracing Keynes as insight into the current state is simply being pragmatic since his theories sanction the actions of those who got us here. The left has been rationalizing the history of those ideas for decades since there is always another person to blame for the economy.
And before this goes down some rabbit hole over Tea Party conspiracies or other non-sense again I’m not saying the man was wrong about everything, or not that he might have some ideas worth taking a look at. In a dark and twisted way if you want to predict the damage to real wealth in this country it would be useful to back feed through his theories. I might do it if I had the wealth to make money off of the market dislocations and bubbles caused by those theories. But that is not the point.
As Einstein put it once, you can’t get out of a situation with the same thinking that got you into it.
As for another point of clarification, the economy was free up until the Progressive Era, at least the intervention was insignificant to terms of indexing the controls to the overall economy, so Austrian Economics or any other classical Liberal Theory of economics can be tracked there. Or if you want something more modern and definitively Austrian you have the so called Austrian “miracle” that put LMV on the map post WW1. After that it isn’t happening. You have the rise of the Welfare State and any theory that didn’t justify state control of the money supply for economic manipulation through spending was history by those who needed the illusion of academic approval to manipulate the economy. .
You can dispute some of the theories but they do have a real world model to work off if you wish to do so. They are not simple thought exercises never practiced. When the US turned into a mixed economy is a matter of debate, but post turn of the century is the usually agreed time range (my money is on the creation of the Federal Reserve).