I think we are both in agreement that there were various factors resulting in the retirement of both Concorde and the Shuttles. As you say there has to be a need in order to sustain such expensive ventures.

Where I think we differ is that while I can see what you are saying about the 'organic' nature of our development thus far, it doesnt necessarily translate into future success in space.

There was a time, though, when it made no sense to cross the ocean. There was a time when only crazy experimenters tried to fly. And there was a time when the raw juice in fossil fuels was insanely dangerous and explosive, and now I buy them by the gallon with the flexpass on my keychain so that I can chase Ferrari Scuderias down Sepulveda Pass at midnight at 120mph.

Yep, there was a economic driver behind all of that and it was built up incrementally over hundreds of years. At each stage of the development there was an almost immediate benefit that could be used in lots of other areas. Geometry leading to Navigation leading to Cartography leading to... until we end up being able to sail small ships out of sight of land knowing we can make our way back safely to shore.

When it comes to space we are dealing with a different beast entirely. How do you incrementally improve your method of travel until you can make the MASSIVE leap to the nearest inhabitable planet (I am making an assumption here that we don't take the longer refueling multistop approach). How do you do it considering that the most plentiful, energy rich fuel that we have is busily being expended in daily commutes to the office.

To get from here to way over there is going to take a long time and its going to take more than we have. If you breakdown half way there is no life raft. We have not come up with anything that could conceivable get us there even with multi generational ships.

Oh its probably clear at this stage that I want it to be true as much as the next person but an honest review would indicate that we are not on a path to achieving it.

Heres an article worth a read I think.