classic bad arguments
The "arguments" were to work, to live, and to survive. The first two were vague nonsense. The "to survive" argument has been argued much better by people on this website, and I still think no one has articulated why we need viable populations off-Earth in the next 50-100 years in order to meaningfully reduce the chance of human extinction. Gary's "we might lose the technological capability/will to leave Earth" (my paraphrase) is the closest, but I'm not persuaded.