I'm sure of that. But what you're leaving out of the balance is how much...well, "geology" is a misnomer...planetary science could otherwise have been done with the same resources? Consider, for example, what it would have cost (in money, time, effort, and potentially human life) for human explorers to equal what Spirit and Opportunity have done on Mars?
More importantly, the probes we design are getting more and more capable over time, as a direct result of our experience in building probes. Robot capabilities will approach human capabilities faster than human exploration will approach even the moon (this wasn't true in the 1960's).
Finally, the fact that machines can go places where humans never can means that even if humans someday do the brunt of exploration in our solar system, robotic probes will always be an indispensible tool.
IMO a healthy and robust program of exploration will include both a robotic and a human component. Certainly if colonization is the (eventual) goal we can't let the manned effort lag too much. I don't see any reason why we can't do both well. Sure, it will cost, but mankind has always had the drive to reach out and explore what is beyond the next hill, the horizon, and the sky. To stifle that in order to pinch a few pennies here and there is to stunt and whither an essential and inborn trait of humankind.
So, I don't buy into this either/or attitude. It is a false dilemma and thus a logical fallacy. Speaking of which, my comment was meant to contrast your earlier comment concerning the ability of robotic missions to do the same and more of what humans could. That was a very broad generalization. In this specific case, the guys got the job done where it was unlikely a remote presence could have done as well. Inappropriate generalizations are also fallacious.