I think you're just mixing fantasy with smaller situations.
Take italy. In the late '40s/start '50s we had the P2 mason, with a lot of people coming from the fascist power classes, The Communist Party getting funded by the USSR, and Operation Gladio, which was the one of the many NATO ''stay behind'' projects to safeguard Europe from possible Communist invasion (in the case of Italy, from Yugoslavia). I strongly imagine that the situation in West Germany was even more conflictual.
Gladio cooperated with P2 to keep the communists down, sometimes even getting them to do something to then address the fault to either communists or anarchists (look at Ordine nuovo if you want some data, tho I'm not sure what you'll find in english).
Then, in the '70s, when forced communism wasn't a threat anymore, the CIA retreated, while P2 stayed as a powerful masons with ties at all levels of the government and the military. They were later discovered and judged at the start of the '90s (and still, Berlusconi was admittedly in it).
But this doesn't mean ''the fascists have been in power ever since''. it's just a series of situations that led old powers to maintain influence over the new structure.

Plus, some same old internet bullshit, like ''Hitler survived''.