I think you make some good points, Doodler, even if some of them get close to political. Some anthropologists define a civilization as having a system for the distribution of wealth and a system for division of labor, which may be minimized in the "make your own way in the world" mentality. I'm not saying you are wrong, just that such a system is considered by some to be less than civilized.
The question is a legitimate one, even if the inquirer in uninformed and asks the question out of ignorant assumptions of reality. Could we have developed some of the spaceborn technologies without going into space? Many communications functions may have been (and may eventually be) performed with landbased radio or landline systems. Making spacecraft lighter may have started the computer revolution, but the semiconductor industry has not been propelled by aerospace needs much since then. Sure, they make good money off of spaceflights, but I would bet they may much more selling PCs and other consumer electronics.
Necessity may be the mother of invention, but consumers are its wetnurse.
Et tu BAUT? Quantum mutatus ab illo.