Few things folks have to realize that those missions to the moon cost billions...just one mission even in the 60s or 70s.
For example the apollo missions in 1974 cost 25 billion which is the equivalent to 153 billion dollars today.
Lets put the 153 billion dollars in perspect. Today the new stealth bomber being built by Northtrop Grumman (qty of 100 planes) is expected to cost between 50 billion to 100 billion in initial and over run costs.
Second when building top secret planes and instruments the government often times destroys the tooling needed to build these items. For example after Northrop Grumman built the B-2, after Lockheed built the F-117 and F-22. The tooling to build these planes were destroyed by the government so they wouldn't fall in enemy hands.
This even came up in 2016 when I believe the airforce asked if congress would give them funding for new F-22s. The cost to restart the program was in the billions. Their reason was that they would have to make everything....tooling, machining, supply chain and etc over again. They even estimated that old engineers from the program would have to be signed back on because no one knew how to build the plane.
See in engineering when they say they can't build something again. What they mean is they can't justify the cost to build it...plus the original engineers who built it are no longer around. Which means they pretty much have to rebuild the thing from scratch.
Which means their is a huge learning curve plus tribal knowledge that only the folks who originally built it understood. Just having something on paper or in a model doesn't tell you all the nuances of building it. Especially something that is huge and an entire system.
shyt that ain't even including technicians, assemblers, testers and etc who all have experience building the product originally. All these people will need to be found or replaced.
shyt is a huge effort. Hell I remember when I worked in DoD years ago. We had a old mechanical unit (that needed to be repaired) come in for a B-52 that was being refurbished. The original maker had gone out of business. We couldn't find anyone who knew how to fix this part. The part was from the 60s. We literally had to find this old 70 year old engineer who had originally helped build the mechanical unit back in the 60s....and hire him to rebuild the unit.