In an Apollo conversation with space historian Dr. Asif Siddiqi, the Fordham University professor went so far as to say that by going so far so quickly, the Apollo program might ultimately have done humankind a disservice—we got to the Moon in a stunning display of technical mastery and willpower, but the Apollo model falls apart without constant outside pressure. By letting us run before we knew how to walk, Apollo might have saddled the country and the world with a wildly unrealistic picture of what a functional, sustainable space program should look like.

Source: The Greatest Leap, part 6: After Apollo, NASA still searching for an encore | Ars Technica

I have said this before myself: the success of Apollo set back space exploration 50 years.