Well said, and all quite true and sensible. My only “but” would be how well human life can truly adapt to life in space. For instance, a spacecraft would need to be large enough that when it spins to create artificial gravity, it needs to be large enough that there is no appreciable difference in the amount of “gravity” experienced by the feet and by the heads of those on board.
Another factor could be the lack of exposure to earth’s microbial biosphere. Yes, we’ve had people in space for many months at a stretch, but how does the lack of exposure to earth’s biosphere affect our health as a species over many generations?
Of course we’ll build spaceships large enough to address the first issue, and hopefully evolution will take care of the second issue (though we can’t yet know that for sure). But in the meantime, we’ve got to keep our own home planet not just prosperous but habitable…and a large portion of America’s population don’t seem to get that fact.