True, but there are all sorts of things that we could do, but we don't because, well because we just don't. There are a number of things that come to mind. One is that novel solutions to problems often come from someone scratching an itch. The problem is, they have to notice the itch in the first place, but the problem domain of, well, basically saving the Earth, is broad and it is hard to see the forest for the trees. The problems to solve for space exploration can be much more focused, and I think that does actually tend to drive people towards developing solutions that can then be applied to broader problems. In other words, for invention usually specific to general seems to work better than general to specific. There is also the matter of drive. Not that drive does not exist for researchers working to deal with environmental issues, but still there might be a tendency for the space fanatic to also be able to maintain better focus. Overall, even if what is developed is never used in space at all, I think that working towards the space-focused form of these technologies might actually bear fruit that can be highly useful here on Earth.