Germany after the second war was devastated and since its defeat. Policies were explicitly implemented to prevent its technological and economic advance in the country. (Morgenthau Plan (1945), established by JCS-1067, a directive which controlled the American armed forces and gave advice to the president.)
Germany stopped growing during this period as the plan established bans on the creation of airplanes, ships, the destruction of ship factories, limitations on steel production and the remaining steel factories were dismantled and industrial research prohibited.
A few years later (1947), JCS-1067 was revoked by Truman and became JCS-1779, its purposes were completely reversed.
The directive now wanted to boost Germany's growth to the maximum. Ludwig Erhard and Wilhelm Ropke started their projects to transform Germany once and for all.
Some remnants of the Nazi Era still permeated German territory and, among them: price control, inflation, production control and the state's direction of the economy. The two decided to remove all of that and boost the economy liberally, reducing taxes, especially income tax, which went from 85% of profits to 18%, reducing currency circulation, resuming a free, uncontrolled price system, and placing the growth of industries to the heights.
From May 1948, until December of the same year, Germany's industrial production grew by 50%.
In 1948, the Marshall Plan arrived in the country, during its great growth, but it only represented 5% of the country's GDP in the year.
What they have been saying about the Marshall Plan being "Europe's economic salvation" has always been a myth, within the German context.