For example, the F-1 engines that powered Saturn V first stage actually began development in the late 50s, with the first static firing happening in 1959. The (in)famous combustion instability challenges of the engine were solved by 1961.
Apollo had a tremendous running start in many areas - to say nothing of having the resources and know-how of the entire US military-aerospace-industrial complex at it's disposal. This isn't to minimize what an accomplishment Apollo was. I just don't think you can meaningfully compare the timelines of what SpaceX is trying to do with Starship, and what Apollo accomplished.