There's a wide variety of ways that easy access to space could help the ecology. Battery technology at the moment needs a lot of rare earths, which could be obtained in space. Mining activities in space are mining activities not occuring on Earth's surface. Solar power may be augmentable using space technologies. Any high-pollution industry that can be moved to space is either polluting something already clinically sterile (remember pollution is not "intrinsically bad", that's a cognitive shortcut that works on a planet with life in every cubic centimeter, pollution is bad because of what it does to life; really, if there's no "life", there's no "pollution"), or "polluting" into something that will just be blown away on the solar wind, which makes it irrelevant. Easy access to space also enables some ways of controlling climate change; I've always preferred the space mirror approach to manipulating the climate because it's so fantastically controllable, unlike almost all other proposals to try to fix it here on Earth. (If you get it wrong, you can stop.)

Also, before you trot out the tired old "oh, we never thought we'd finish polluting the ocean"... first, run the math, it's very different, and second, the universe is already terminally polluted, in the sense that nothing much can live there until we go out and clean some space out. There's no life out there, not within anywhere we can get in your lifetime. It can't get any more uninhabitable than it already is.