You do realize that space flight has been pretty much stagnant for the last few decades. Before SpaceX came in and started reusing boosters there was pretty much 0 innovation in propulsion tech. So just throwing in the towel from the get go is a bit silly.

Besides there are plans to move industry to space, it's the entire reason NASA is restarting their moon base ambitions. And news flash: moving heavy industry away from earth will already do more for the environment than any pollution reduction program ever could. Most of the toxic trash we are stuck with gets produced while turning the raw materials into something usable. The rest of the trash is comparably a drop in the ocean.

I'm not thinking too sci-fi here, this is all pretty reasonable to do given moderate advances in rocket tech (the only major problem I see is added green house gases from rocket fuel so that's something to look into I guess)