And you fail with "that time's technology": The technology the NASA used was good enough for a flight and a landing on and a starting from the moon. And they didn't want more. They only wanted to reach the moon, land, walk around, take some rocks and fly back.

The reason why they didn't do it after 1971 was because it was the most expensive science-program in all time. The USA were in high budget problems, mostly because of the Vietnam war, and couldn't afford to pay so much money to the NASA anymore.

And in that days they hadn't really an idea, how to live on the moon. They had the dream, but they didn't know how they could do it, because they'd not found water and oxygen on the moon at that time. So they thought that they would have to bring EVERY material from the earth to the moon, and that was much too heavy for that time, in technology and in price.

So they dropped the idea, and one question: What reason if not living on the moon for science or perhaps for industrial production is there to make a flight onto this dead, cold, evil piece of rock? No reason, so there was no will to go to the moon quite soon, it was more important to place satellites and space stations into the earth orbit for science and enhanced communication.