> It has always annoyed me that there's a loud contingent of people that object to human space travel on the basis it's not the most efficient way to conduct science...

Sometimes I actually blame Skepticism.

I'm not talking about skepticism mind you, but Skepticism-- the capital-S variety that became so popular in science starting in the 1970s as a reaction against things like the new age and the resurgence of religious fundamentalism. Rather than an attempt to keep the candle of science burning, I've started seeing Skeptics as another manifestation of the general turn toward superstition that occurred on or around this time. Theirs is the superstition of the known-- the belief that that which is not presently understood cannot possibly exist. Skepticism also usually fellow-travels with the kind of deep conservatism you're talking about. Head over to Skeptic boards and you'll see that the general opinion is anti-manned-space-flight for exactly the reasons you state-- it's not the most science for the buck, etc. It also usually fellow-travels with eco-doomerism for the simple reason that no comprehensive solutions to our current energy problems are known therefore they cannot possibly exist. (That which is not known can't possibly exist, remember?) Skepticism raised a generation of scientists whose first instinct is to tear things down and narrow the range of possibility.

My personal big overarching theory on the dark age of the 70s is that there was a broad shift toward conservatism and fundamentalism across the entire spectrum of human thought: right and left, scientific and mystical, etc. As for why I'm not sure, but I suspect that fear was a big part of it. Lovecraft said it best:

"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the deadly light into the peace and safety of a new dark age." - H.P. Lovecraft, "The Call of Cthulhu"

That's exactly what I think happened: we fled from the deadly light into a whole grab bag of comforting, pessimistic, conservative absolutisms. Apocalyptic fiction is so popular for the same reason-- people find it comforting in a weird way. If we're all doomed then at least we know what the outcome will be... unlike more optimistic visions of the future that end with black voids like "the singularity," human genetic metamorphosis, alien contact, the birth of AI or other post-human intelligence, etc. I think there's a part of us that finds the unknown more terrifying than death and that secretly hopes that WWIII or ecological collapse will save us from the great unknown outcome of progress and exploration.

If I had to stick a marker in the ground, I'd place it at the moment everyone saw that earth rise shot:

http://www.nasa.gov/sites/default/files/styles/946xvariable_...

See any gods in there? See anything that cares about us? Nope. All I see is a tiny grain of sand in an endless black void of nothingness. We are basically dust mites living on that grain of sand. This photo basically proves that we know very little about where we are, where we come from, and where we are going. People looked at that picture and said it was beautiful and inspiring, but secretly somewhere deep inside I wonder if the reaction wasn't metaphysical horror...

Stare at it for a while... you'll see it.