If your space habitats are colonies in the classic sense of the word, that means they are appendages of powers on the homeworld. They exist to go get resources and bring them back, so that the rich and powerful on Earth can live more comfortable lives. Thus, no matter how oppressive and exploitative the management of the colonies may be, there's a fundamentally hopeful outlook in such a setting. The powers that be are looking outward, seeking to despoil the rest of the solar system in order to avoid destroying their own backyard. Obviously, it can be done badly, and result in everyone dying off anyway, but the core tone is that there's always more to be had over the next metaphorical hill...and if you can successfully exploit the resources of the entire system, it's gonna take a loooong time to run out.
If your space habitats are retreats for the rich and powerful, though, you're probably not going to have grandkids to tell your stories to...if you live long enough to have kids in the first place. If those in power have ceased to be personally invested in the fate of the Earth as anything but a source of materials to exploit, it's always going to be cheaper and easier to strip-mine the planet than develop ways to use extra-terrestrial resources elsewhere in the system. And with far fewer residents on the "world" being supported (rich people on Earth will at least be reluctant to do something that cracks open the crust and turns the planet into a molten mass), even when it starts to look like there's only a few decades left before Earth becomes unlivable...well, it won't require nearly as much work to mine Mars or the asteroids to supply a few space habs. And hey, once more of the people on Earth are dead, the planet might start recovering, so even if the rich and powerful take a longer view, it's not a view that includes humanity as a whole.
In short, if it sucks to be on a space colony, life on Earth is more likely to continue for a good long time. If space habitats are a paradise, Earth will fairly quickly become a purgatory.