Can you think of any other exploration venture in the history of mankind that was ended as quickly as the Apollo program?
There was a reason for it. It was an enormously expensive undertaking that could not result in any long-term human settlement except in completely artificial environments.
It was an enormously expensive undertaking
"Enormously expensive" is a relative term.
The entire Apollo program from 1960 to 1973 cost $28 billion.
Meanwhile, the US spent $28 billion every 3 months in 1969 for social welfare programs.
Let's let that sink for a moment - one of the greatest achievements in man's history, an achievement that continues to have a profound impact on our current-day technology and which inspired untold numbers of children to become interested in science and engineering, cost as much as three months of social welfare programs, many of which were misguided or counter-productive, a few of which actively helped break up families and destroyed communities.
Apollo was an enormous bargain, if what we're focusing on is monetary cost. There are arguments to be made that space exploration should be privatized - I agree, but there is a national security component to space exploration and settlement which means the US government must remain involved and active with its own programs. There are also arguments to be made that robotics and automated exploration should lead the way - again, I agree completely that AI can and should be used, but in the short term it's insufficient. In the long-term, I don't think we want to become a nation of bloggers looking up occasionally to see Mars Rover-quality pictures from the surface of Mars, where the Chinese and others will be setting up manned bases.