Keynesian ideas were bankrupt to begin with. Gold was not $215 in 1933 . . . Gold was around $21 . . . the $20 coin that FDR confiscated had almost one ounce of gold in it. Try to explain how gold went from $21/oz to $215 without inflation.
Keynsian ideas did not even save American economy (or German economy for that matter, as Hitler too adopted a Keynsian economic program; e.g. the Autobahn building) . . . all the government spending, taxing and inflating only served to prolong recession into the Great Depression. Americans actually had a very good idea that such big programs didn't work. The big Keynsian programs did not start with FDR, but Hoover . . . remember, it's called Hoover Dam not FDR Dam. American voters elected FDR on the platform that he would terminate all of Hoover's wasteful government spending programs. Well, the compulsive lier FDR ran his administration exactly opposite to what he promised during the campaign (just like his stand on keeping Americans out of war). The result? prolonged economic recession and war, and the American Empire, with promises of even more American blood and treasure wasted so that someone in the clique could get rich off those big government programs.