Wouldn't explain the continued relevancy of others that have withstood the test of time.
I also think that the changes in our world are largely cosmetic. We don't have to go downtown to the library to do our research, but we still have governments discrediting do-gooders or those who think outside proscribed boxes, and crimes predicated on race and so many other damn things that are the same that it isn't funny.
I grew up in the 70's and 80's and I think the world is a far different place.
I can easily see where some stories simply wouldn't work for newer audiences, even though I love them. One that I would point to right off the bat is The Conscience of the King
(an episode I love). My daughter asked a very straight forward question when she was a bit younger: why don't they simply do a DNA test? I know and you know that wasn't even on the radar in 1960's storytelling. But I could easily see it being a stumbling block to someone who has known about DNA almost their entire lives.