I feel scenario B is indeed possible: Sophisticated cultural overlays that modify our interaction and impacts on the biosphere are obviously within the nature o

I feel scenario B is indeed possible: Sophisticated cultural overlays that modify our interaction and impacts on the biosphere are obviously within the nature of the system. A key question is whether the feedback signals from the biosphere will be strong enough and will be internalized deeply enough to usher a sustainable era. One can only guess, since we haven't really experienced anything of this sort before. But logically, if scenario B plays out and we enter a sustainable phase we would be sending out technosignatures. Hence if a similar process has repeated across the universe we should at some point see evidence of advanced life that "just made" it. The fact we don't may mean its not possible. But I would not read too much into this pessimistic conclusion because we may be missing important other dimensions regarding the nature of life and its co-evolution with technology. We should strive to survive independently of what else might be happening in this mysterious Universe :-)