>>17795167 (OP)>As a continent it's very habitablenigga they made it habitable
They've been practicing slash-and-burn agriculture and semi-permanent lifestyles for millenias. If it weren't for the natives, most of the East Coast for example would be heavily forested, not the "very habitable" place you - or the puritans that made up the first english colonists there, for that matter - know today.
I'd have said, give it a few centuries, and the Injuns would have eventually mostly settled permanently. Given examples like the Haudenosaunee, the Wendat and the Muskogee/Mississipi Injuns forming somewhat sizeable confederations, I'd say it was well underway. The fact that there were semi-civilized outliers already developping or having developed in the past in some particularly plentiful or harsh climates like Cahokia and the Pueblo only point this way.
tl;dr they made the land fertile and were getting there