1. I said for colonization in space to really take off, there must be economic payoffs or at minimum, enough in situ resources to defray resupply costs.
2. Right now the cost to orbit is so high, that it would be very difficult to meet criteria (1)

My other comments were responding to really silly arguments against my almost self-evident statements. Yes, in order to meet criteria one we need either or both, somethiing to trade and basic living off the land resources. Right now the only thing that can be traded is knowledge. We don't have the technology to mine asteroids in a cost effective manner that could be traded to earth. We don't have the technology to cost effectively put up solar power satellites. And basically we don't have technology right now to do anything, but return knowledge. And the most cost effective way of doing that has been and will continue to be for some time the use of robotic probes.

And we can't really project any cost effective colonization that could occur with current technology. The best we might do now is some sort of antarctic like science outpost. As I state that could change if we radically lowered cost to orbit with something like a space elevator, but we are probably looking at 50 years before some technology surplants chemical rockets and lowers cost to orbit by at least order of magnitude.

I really am baffled by the arguments against my statements about the most successful "colonies" have most all the resources to prosper in situ. This has been true throughout the pre-history and history of man. Man first cherry picked places like river deltas, and lush forrests. These had game, fish, arable land, water, and reasonable climactic conditions. Of course trade developed and was used, because by its very nature trading partners are both gaining something. But my point is that the viability of the original settlements were not totally dependent on trade, and only grew dependent on trade over time because economic resupply usually from mulitple sources could be relatively guaranteed.

Why isn't there a huge trade with antarctica? Unfortunately antarctica is the closest analogy to our current relationship with space. It is a harsh environment, that has some unique characteristics to gather knowledge. But antarctica is expensive to resupply. Yes, because it is a harsh environment, a lot has to be supplied to it in order for the people to survive. Now, if we find some giant gold asteroid buried in antarctica somewhere, all of a sudden there would be something to export and you could develop a mining colony. Still, it would be limited because it is still a harsh environment.

Yes, I believe we will eventually colonize space. I think eventually we will have a dyson swarm and possible trillions of humans living off planet. But no, I don't share those that believe this can magically happen if only the govt spends more money. We are still missing some key technological advances for off planet colonization. My read of history tells me only when sound economics are in play and market forces can generate a positive feedback loop will any substantial growth occur. The advances of private companies starting space tourism are clearly the most viable current attempts to start this feedback loop right now. It remains to be seen how quickly the process can be bootstrapped. But it is still difficult to see how they can break pretty significant barriers to cost to orbit, until they've built up a very significant cash flow that can fund some still yet to be determined technology breakthroughs.