Your question is actually examined in history research. Generally there is something of a ,,forgetting curve'' for historical events, after which they leave the general societal awareness. (Of course estimations are hard, but around 50 years = 2 generations seems reasonable) WW2 and the "Holocaust" are widely credited as falling outside the curve, meaning the events are much more salient today than would be expected given the length of time elapsed. Of course the singularity of the horrors plays a role in this, but some historical researchers do not believe this to be the main reason. Compare the general knowledge of WW2 with the knowledge of WW1, nearly everybody knows Stalingrad, Auschwitz, Pearl Harbour, but who remembers the Battle of Ypres?

One theory is that WW2 and the "holocaust" have a special role, because the weirdness of the period following it. Because of the fight against communism, the USA and West Germany nearly instantly became allies after WW2 and occupation with the horrors past became discouraged. For example Hans Globke, one of the authors of the Nuremberg race laws, was allowed to be a high ranking minister in the Adenauer administration and some believe he was the reason why Germany and the CIA were not very interested in finding and prosecuting Adolf Eichmann at the time.

That is why there was a certain time lag in considering the events of WW2. In Germany there were the student revolts around 1968 and in 1969 the German chancellor Kiesinger had to step down because of his "nazi past" - which in comparison to Hans Globke was totally harmless. In a similiar vein the word "holocaust" mainly comes from a US TV-Series in 1978, the preferred jewish term is the "shoah".

I guess we will have to wait until the 2030s or so,to see if it still overshadows everything else then.