That is because The US lost the focus of the space program. They decided after Skylab that "Okay, I guess we can just sit back on our asses and watch the shuttle go up every 90 days or so."
The shuttle program is sadly one of the biggest wastes of tax dollars in U.S. history. There was real potential to change commercial aviation with the project, but instead, the shuttle became the billion dollar taxicab that ferried people to and from the billion dollar tin can.
What are we gaining out of the space shuttle. Sure, it is cool that we have the technology to blast millions of pounds of stuff into outer space, but what are they doing when they get there?
The hubble was really the only useful thing that the shuttle did, otherwise there was nothing.
We will Endeavor to waste all of our tax dollars in the Discovery of new ways to waste the tax dollars, by naming our rockets names like Atlantis to make people think we are actually thinking, and then we ran out of rational names along with rational ideas, and along came Columbia.
The mars missions and the Idea of the space station on the moon is really where it's at. We are finally remembering the dream of the oringinal astronauts. Discovery.
Seriously, did Discovery really discover anything?
And all at once the crowd begins to sing: Sometimes the hardest thing and the right thing are the same