This is a brilliant analysis of possible futures, given our current overshoot predicament. I strongly doubt, however, whether the endless growth/colonizing the stars option is anything but an idle fantasy for delusional narcissists like Elon Musk.
I totally share your perspective, which was aptly summed up by Norman Myers back in the ‘80s: “We have two choices: a Gaian future or No Future.” While our industrial Glomart (short for “Global Market Economy”) civilization was doomed from the outset to the latter option (“no future”) as you ably illustrate, I, like you, am wholly committed to pursuing a Gaian future, right up until I myself return to Gaia through a composting burial after I die— thus living by my Gaian principles even after my body returns to topsoil…Since my own influence on the world is only slightly greater than that of a hamster, I am pursuing my Gaian future humbly by devoting my remaining days to learning and teaching Permaculture (Gaian praxis) by growing gardens, growing community, and growing awareness.