I don't think one can put a end point to Apollo. More a series of acts starting with the march on Cape Canaveral the day that A11 launched. That brought into focus, I believe, that the countries priorities were not in beating Russia to the moon, as this would be completed very soon. But that those in Congress were not willing to continue funding a large program when the Great Society beckoned funds as well as the Vietnamese war.
I think it might have been be stated by Frank Borman in a NOVA(?) documentary, where he stated the "Americans weren't interested in exploration, but they were damn interested in beating the Russians".
So in a way the program died of success.