The aspect that's depressing to me is that we've shown many times that we can throw huge amounts of resources at various projects, numbers quantifying them so large most people don't have the context for the scale, but not for projects that preserve our environment. If anything it seems like doing so would give us a greater time span to do things like colonize the nearest chunk of rock in space (which is a figurative paddle off the coast compared to reaching other habitats) and terraforming our own world first might teach us things we need to know for greater projects.