I'm as far from a 'free market religionist' as one can get. I'm a ridiculously left-wing hippie-dippie liberal. To me, this isn't about some sort of mad faith in Adam Smith's Invisible Hand. It's simply a reaction to the fact that our government would rather allocate huge sums of money to things OTHER THAN manned space exploration.
For instance, the military. And the contractors that support the military.
NASA's budget has, quite simply, been far too small to support an envelope-pushing manned space flight program for quite some time. Witness how the Shuttle (1970s tech!) was used into the 2010s. NASA's manned spaceflight program stalled some time in the 80s and never really recovered. (It may have been the Challenger tragedy that made funding NASA significantly harder; I don't know. I'm not a politician, nor an economist.)
Quite simply, the government ISN'T doing it. And it probably won't, for the forseeable future. Who does that leave, with the kind of money to go to space? Corporations.
It's simple logic. Has nothing to do with 'the corporations are better than the government' or any sort of rhetoric at all. It's just "[X] isn't doing it, so [Y] is gonna try, because it's something some people want."