I, too, am disappointed that manned space exploration sort of just stopped with Apollo, and I have long wondered what could have been, but . . .
A quick google tells me that the Apollo program cost about 2.5% of U.S. GDP annually over about 10 years (I remembered 3%, so that is in the ballpark). You can begin to understand why the U.S. government and the public at large decided that the rewards maybe weren't worth the cost. It is still somewhat unclear what benefit we get from spending massive (but relatively much smaller) sums on manned space travel (and to be clear, I wholeheartedly support it regardless).
Manned exploration is expensive and risky. In general the science-per-dollar is much higher for unmanned probes. I won't claim on-premises analyses can't be helpful, but the ability of bots to survey more areas usually offsets that advantage. The real benefit of manned missions is learning how to live in space for future colonies and long-distance travel. Space is not easy on the body, we'll have to figure out how to adapt if we want to spread.
Some try to dress it as science, but when people find the truth, they feel mislead, and want to yank all the funding in frustration. But like I mentioned, it is "body science" and survival lessons.
> It is still somewhat unclear what benefit we get from spending massive (but relatively much smaller) sums on manned space travel (and to be clear, I wholeheartedly support it regardless)
The two sides of this question were already perfectly argued 54 years ago.
German Rocket Engineer Helmut Gröttrup (who didn't want to leave his family to join Operation Paperclip and was then instead forced by the Soviets to work for them in Russia until he managed to get back to West Germany) said in 1969 (Wikipedia):
> In an interview on the occasion of the US moon landing in July 1969, Gröttrup criticized the high costs of manned spaceflight and confronted Wernher von Braun with the thesis that automated space probes can achieve the same scientific data with an effort of only 10 or 20 percent of the costs and that the money should be better spent on other purposes. Von Braun justified manned spaceflight with the argument that "it would help humanity achieve immortality".
Also, we have yet to find a way to prevent the profound adverse effects of prolonged periods of weightlessness on the human body, which is why there are still zero permanent residents of space--contrary to expectations at the start of the era of space exploration.
We do have a way--large rotating cylinders--it's just expensive, and hard to engineer depending on the method. If Starship can really bring down launch costs per ton anywhere near what Elon claims, it will finally become feasible.
A quick google tells me that the Apollo program cost about 2.5% of U.S. GDP annually over about 10 years (I remembered 3%, so that is in the ballpark). You can begin to understand why the U.S. government and the public at large decided that the rewards maybe weren't worth the cost. It is still somewhat unclear what benefit we get from spending massive (but relatively much smaller) sums on manned space travel (and to be clear, I wholeheartedly support it regardless).