It doesn't surprize me that NASA ground computers were prehistoric in the 70's. Once NASA rates something, they never change it. Not even to update the OS. It's a reliability thing. They probably kept those computers until the late 80's. The JPL computers I worked with in the 1980's were in the room with the Voyager machines, which were second hand ModComp computers taken from Polaris submarines.
The computers in the LEM and CM were very small (maybe 4k, I don't know), and required much human interaction. The pilots basically had to load each program for each flight phase. The program monitored conditions, and computed angles and burn times. The last of the modern HP calculators were way more powerful. But the Apollo computers were enough. Just barely.