While the merits of going to space are certainly arguable, stating that we haven't gotten very far from earth since 1980 is particularly irrelevant. We have been to the moon. We could go again, for less money, if we wanted to. Does the fact that we have decided not to have any bearing on the economics of spaceflight?
The linked article is not particularly convincing. Rather than begin with a short introduction and then present factual evidence for why space is infeasible, the author complains emotionally about the entertainment industry and how the public in general has inaccurate views of space.
Then he goes on to say that space is big.
Then he tells us that space is dangerous.
I seriously found it hard to finish this article. At some point the author says that if a life dingy is lost at sea edible fish may jump aboard (has this actually happened?) but hamburgers do not hit the side of space ships...Really?
Also, he says that biospheres have not been successful even though they have:
http://en.wikipedia.org/wiki/Biosphere_2
Though the crew reported hunger, they were able to survive for two years without importing anything at all from the outside world. Though not the best possible outcome, it was essentially (to my knowledge) the first time any one has attempted to do this, at least on this scale. No doubt our technique would improve with additional research.
I could go on...but the truth is that the only thing this article proves to me is that the author doesn't want space to be a feasible option.
I am convinced that we are currently biding our time and improving our technology. It makes little sense for us to spend a ton of money getting someone to Mars now if in 20 years we can do it for a third the cost. My bet is that we will start serious space exploration in as little as a hundred years (even I am not that optimistic). But to say that the space age is dead never to be recovered is ridiculous.