Going to the moon wasn't pure science research. Such research could have been an alternative use of those millions of man-hours of effort.

That said, I do take chriswarbo's point that it could have easily instead been even more baroque weapons or proxy wars, as well as yours and manaskarekar's about the uncertainty inherent in counterfactuals. I just wanted to make the point just finding some positives is not enough, you need to look at opportunity costs. If we both look at them and come to different conclusions, that's life, but at least we agree on the basis of measurement.