In addition to our having lived it as adults, I also believe the current past of 20/30 or so years ago seems a lot closer than WWII did in 1960 because we have video of that era made available to us on demand, some of it in HD, while 1945 was not nearly so accessible to the people of 1960. In fact, I kind of wonder whether WWII feels closer to me now than it felt to me 30 years ago because so much of the account of that time (video, newspaper, etc.) is available to us now in a way the couldn't have been back then.