So if all this unspoilt wilderness is available for flying off into the sunset in, why are all the flying billboards exhorting everyone to settle offworld?
I can think of reasons. First of all, if a significant part of the country/world has been stripped of resources and animal life, whatever is left might be incredibly protected: in other words, it might not be legal ot live there. Second, people tend to want to live where it’s convenient, even if it’s a shitty place to live.
Could be that living offworld really sucks, so nobody wants to do it, and the Powers That Be™ are spending truckloads of money trying to convince people otherwise.
Not unlike Bush’s Social Security “reform” plans… 