An awesome post that deserves wider appreciation. 

Re adjacent possibles. I've been thinking for a while in terms of soft landings and I think these have to do with timescales. It may be that there's a stable sustainable 1000 year future with 100m to 500m humans on the planet. Take the mid point. Getting to 250m from 7b could be via a catastrophic collapse that happens in 10s of years in which case it will be particularly horrific. That's the hard landing. Or it could be spread over a 100 years in which case it could be accomplished via a small drop in the birth rate. That's the soft landing. I'm absolutely sure that the current system is completely unsustainable in the 1000 year time frame. But I'm still holding on to the belief that we can find and get to an adjacent future that is reasonably fun to be part of. That's a belief that it doesn't have to be a catastrophic, chaotic collapse and die off involving large scale war, pestilence and famine.

The challenge then is to turn the 100 year and 1000 year sustainable futures into a 10,000 year future. A Long Now to the tune of the Long Player, Anathem style.