And Jamestown would have vanished entirely -- or indeed, never been founded -- if not for tobacco exports.

The Puritan settlements in Massachusetts were perhaps less export dependent, though in that case it required that the cost of creating a colony be low enough that a moderately well-off (and highly motivated) group of private individuals could start one, with some assistance from the crown. Given the desire by the English to claim and keep large tracts of North America, if only to keep the French and Spaniards from doing so, they were willing to subsidize the colonists significantly. Exports of salt cod and other commodities also helped pay for things the colonists could not produce themselves.

Land as pleasant as the Pacific NW or northern CA would have seen some subsistence farms move in no matter what, but what really got settlement of the West Coast going was first, the fur trade, then the gold rush and in the NW, the production of timber and foodstuffs to support the gold miners. The "pioneers" were never self sufficient; they imported all sorts of manufactured goods from the East Coast, even finished lumber was shipped to Oregon, in exchange for the valuable commodities produced there.

And what would the population of Namibia be if not for diamond mining? How many people stayed on South Georgia island once whaling was done?

Unless there is some sort of valuable economic activity to be done on Mars, I just don't see colonization happening. Who is going to pay for those 1,000 people to go to Mars, and why? Why would they rather have 1,000 people there than to put a few tens of billions into developing automated equipment to do the vast majority of whatever work it is that's going on? Who is going to pay for all the supplies and support those people will need for a long, long time?