Interesting stuff & I couldn’t resist chucking in my tuppence worth. Maybe the potential sustainability is actually pretty irrelevant. Barring some sort of mass spiritual awakening, the only reason western “civilised” populations would return to the land would be as a result of some massive catastrophe – nuclear war, meteorite strike, sudden cataclysmic climate change, wildfire epidemic disease etc etc. In this case, there would probably only be a relatively small population of survivors. These few could scavenge off the carcass of our technocracy for some time, whilst the ecology recovered and they painfully re-learnt the skills of the hunter-gatherer & subsistence farmer. I think life would be rather brutish and short for most, but I’d like to think there would be a few wily bushcrafters able to escape into what’s left of our remoter wildwoods and sit out the storm in relative comfort.
Maybe I’ve read too much post-apocalypse sci-fi!
Ted W