Given that there is very little interest in developing commons here on earth (especially new types of commons from whole cloth), the shape that "making uninhabitable planets habitable" would likely take is that of living in bubbles rather than some kind of broad-scale terraforming. This would intrinsically shape society towards top-down authoritarian control, rather than allowing for distributed individual liberty. In this light, Earth's bountiful distributed air, water, and wildlife should be viewed as a technological-society-bootstrapping resource similar to easily-accessible oil and coil stored energy deposits.
It's not "handwavy logic". It called reasoning based on heuristics developed from many observations (ie wisdom).
From what I've seen here now on Earth, large scale coordination of projects where the benefits end up mostly diffuse is effectively impossible, especially in the modern environment. Thus private ownership of scaled back projects, organized by corporate authoritarianism as we see for most businesses here now on earth.
Could we possibly have an Earth country/company developing open-space terraforming, investing with the idea they will develop owned colonies, but then a popular revolt throws off the authoritarian control and institutes distributed rights (ala the American Revolution) ? Sure, that's possible. But that also just seems unlikely to be given modern information systems facilitating large scale surveillance, sentiment control, and promoting singular authoritarian perspectives. Like we're currently in the process of rolling back those hard-won distributed rights here now on Earth ("slowly at first, then all at once").
your heuristics is "last 50 years of US history", and you've now applied that to "That's how the whole multi planetary blob of humanity will operate".
I think "handywavy logic" is now being generous.
What about widening your heuristics to consider all of human history and see how much more freedom, autonomy and large scale coordination we have in place compared to say... the dark ages, or earlier.
