The best decision that nazis ever made was not to indiscriminately purge the military and bureaucracy. Purges certainly did happen but they were focused on the political class and very targeted elsewhere.

They kept the systems people depended on running well to not immediately create massive public backlash... they also got lucky as hell. The military and populace were deeply bitter after WW1 and they leveraged grand gestures to great effect while changing relatively little administratively. The fucks in the US are making flaccid grand gestures while tearing down systems people actually depend on.