I was born in the late 1960's. That's 20 years plus a a few years since World War 2 ended and the death of Hitler. That 20 year period seems like an incredibly long time to me.
Nowadays, 20 years doesn't seem so long. 20 years plus a few years was the early 1990's. That's not long ago. That's when Jurassic Park and Terminator 2 came out. Pearl Jam and Nirvana were creating the grunge music thing. Heck it's in the ballpark of almost 40 years ago since Star Wars came out - I remember queuing all the way around a city block to get tickets. Now sure that seems a long way back, but not the distant past.
I feel like history is being compressed by bright, full colour technology like film, colour TV and computers. Anything that happened before bright, full colour technology, heck that was LONG ago. Anything from the era or bright, full colour technology feels closer in time.