1969-06-20 (Orbit Yuri Gagarin) - 1961-04-12 (first moonlanding) is slightly over 8 years.
You forgot 1 little detail.
Apollo?/Saturn consumed c5% of the entire USG budget while that budget was inflated due to running the Vietnam war.
Today the NASA budget is 0.9% of USG spending. There is no clear goal for SLS or Orion (both of which have kept shifting) aside from shovelling cash and jobs into the Senators states that support it.
Remember they chose to put big jointed solids (which cannot be shut down) on SLS after Challenger showed what happens if the joint fails.