Now that we have one. Serious money was put into it. Now it is up there with not much to do. The earth imaging mission is handled by recon satellites good enough to spot a cigarette pack lying on the ground. The astronomy mission is well in hand at Hubble. They aren't enough tourists with money to make an orbital tourist hotel work.
According to Aviation Week, they have space to spare for more scientists and experiments. The only work on going is "micro gravity" (we used to call it weightlessness) what ever that means. Could it be that the best part of ISS was the "International" part of the name. That helped mightily at funding time.