Just a very tangential thought here, but what gets me about 2001 is the idea of what would be economically viable. Sure, it could be possible to have commercial travel into space, but for what? Where would the demand come from? And where is the rest of sweating, starving, striving humanity? To me, the film is parable, not prediction.
They say that mankind evolved in Sub-Saharan Africa. Do you think there was any point to him spreading to other continents? Where did the demand come from? What was the point? Did it help him in the long run to expand to the other continents?
I'm not talking in any philosophical sense here, I'm talking about the nuts and bolts of the future as portrayed in the movies. If all of the resources that went into developing current microprocessors, the internet, and the like were funneled instead into the sort of space exploration ventures we see in 2001, much of that might have come to fruition. The reality, though, is that those resoures instead followed profit and dissipated into more mundane human endeavors on earth. I'm not talking about the way things should be, I'm talking about the way things are.