This is an extremely common phenomena in computer science and related areas.

A huge amount of stuff that we see now was already conceived of and often elegantly mapped out in the 60s or 70s.
It's the Iron Man meme, "I'm limited by the technology of my time" a thousand times. They simply didn't have the processing power to do the things they thought about. Occasionally they had everything but one bit of magic insight which makes things work.

It's kind of annoying really. I've got a degree in Computer Engineering, and there were dozens of times throughout college where I had what I thought was a brilliant idea and it turns out that someone already described it in the 60s.
Even now, stuff that gets popular as "the hot new thing" will have some old forgotten paper. Like, I don't have the link handy, but I just read a thing about Map/Reduce from when it was blowing up, and a researcher pointed out that it was already described in the early 80s.

A lot of the sci-fi writers of the time pulled from real research and just made some logical leaps.