Please, how many preliminary missions led to the few apollo landings? (mercury, gemini, 1st apollo missions). And you can't just isolate a few missions that may have actually used 10% of time for science while the rest had 0 and say we had 10% science return.

Secondly, the race to the moon was politically motivated more than science and technology motivated. It really made no sense as part of a sustainable space effort. We have paid for decades for that largesse and the entire space program was slowed from where we could have gone (especially robotically). Those massive expenditures for the Apollo program dead ended our space program. I can be awed and proud of Apollo accomplishments and still rationally say that it was the wrong thing at the wrong time as part of master plan to explore and settle our solar system. Also, we could've probably returned samples from more sites (and smartly too since teleoperation is practical on the moon), if we had gone the robotic root for the same money.

Thirdly, robotic technology has advanced tremendously since Apollo days while our cost to orbit has not dropped. The tradeoffs from 30 years ago are now much more pronounced in favor of robotic exploration.

Finally, tell me how much science return has come from ISS for the money? My god we have funded the ISS and Shuttle the equivalent of (double?) our entire unmanned space program. All the probes and science returned vs practically zero, doesn't support your claims. If we were concentrating on science return through unmanned space program, how many more probes and fancy telescopes could we have fielded? How much more advanced would our robotic program be, which would lead to even more cost effective return? Think about the ISS and any manned space vehicle. How many components, safety features, design issues reflect the need to house and protect humans? How many supplies? How about the increased overhead of the safety and complexity of the launch and the need to return to earth? Everything is so much simpler without humans. Even on earth we recognize that deep sea exploration is better handled telerobotically for the money. And with virtual reality interfaces you don't lose anything (seeing through a portal is no better than through a camera).