"Why isn't there a huge trade with antarctica?"

You can't buy land in Antarctic. Do you want oil wells in the Antarctic? Want gold mining?

"People from all of these 12 countries met in Washington, D.C. in 1959 to draft and sign the Antarctic Treaty.

This treaty meant the entire continent was to be used for peaceful reasons. It came into effect in 1961 and all claims on land were put on hold. In 1991, 24 nations approved a protocol (addition) to the treaty that would ban oil and other mineral exploration for at least 50 years."
whats_it_like_in_Antarctica

They almost did the same thing with the Moon Treaty- fortunately wiser people prevailed.

"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."

Well analogies are analogies- a "sort of like" or a model for some particular idea. Antarctic lacks some important things- such as a low gravity well and a vacuum.

"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."

Being that it is illegal for any mineral exploration in Antarctic if someone stumbled across giant gold asteroid it would be interesting because certain people are allowed to take meteorites- and some of them are worth more than the gold lb for lb, but if it's gold, people might connect this with mining and who knows what commotion this might start [legal proceedings, senate hearings, etc]. Now of course Moon dirt is worth more than gold- and there is no shortage of moon dirt on the moon. And a 100 tons of water is worth more than a 100 tons of gold on the Moon.

"But no, I don't share those that believe this can magically happen if only the govt spends more money. "

I completely agree. I would be fine if govt spends less money on space. I'm ok with current direction which doesn't have much of an increase and it explores the Moon and goes to Mars, etc.

"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."

Yup, I think sub-orbital travel could be a significant factor in opening up the Space Frontier. And I want NASA to help in making this happen, also.