I share your lament Bob. It does feel like America's drive for acheivement has been limited to how much more we can fit on an ipod or through the internet. If there's no profit in it, it doesn't get done anymore. Check that. If there's no immediate profit in it it doesn't get done anymore. I think we've acknowledged that the benfits of space exploration aren't happening in our lifetimes, and as such, there aren't large numbers of people willing to give up large sums of cash for their grandkids' potential benefits. It sounds dumb, but then this is a culture that won't buy a hybrid car because the gas savings don't match the cost of the car for years. Screw conservation and go for the cheapest option in the now and worry about $5 gas later.
I'm not sure when the dreamers in America died. I'll agree with others, the colapse of the soviet union led to a period of no competetion to keep Amertic on its toes to the point where we got so lazy we don't care if China beats us to whatever's out there. In addition, things such as the demise of big innovator companies like Enron, and the destruction of several established business models by the internet has scared off all but the most entrepenurial spirits, as has a surgence in Ayn Randiism convincing people to put energies into villifying their "opressors" (I say with a certain level of sacrasm), instead of trying to succeed in spite of said "opressors". Complaints of elitism, and backlaash against scientists for global warming and evolution theories hasn't helped either.
And again, I can't rule out impaitence. There were centuries between Columbus, the Pilgirms, confederation and even the 50 states we have today. We can't expect mars colonies overnight, especially if we don't work toward it.