I've seen an analysis which said that the revenue source isn't going to space and back, but going really fast between 2 points on earth. The analysis basically said that with mail delivery you pay up to 5 times as much for the fastest delivery tier as you do fo the second fastest and that there are about 10% as many deliveries at the fastest tier as at the second fastest. So if you could use space ship 2 for an even faster tier and could get 10% of the current fastest market for 5x the price, then there should be enough mail to pay for up to 1 flight per day across the country.

Jerry Pournelle once suggested that while there is no place to "go" in space, that "doing things" in space was always entertaining in its own right. And by "doing things" he strongly hinted that he felt that "doing it" would be the strongest driver.

I expect he is correct, and don't doubt for a minute that if the Bigelow Space guys figure out how to deploy a hotel in space, an entrepreneur will deploy a bordello.