As you have pointed out, it doesn’t seem possible that renewables can replace the status quo. It seems evident to me that a human population die-off is inevitable. Maybe as a species, though, we’ll get lucky and not even notice a relatively quick die-off.

Continued resource scarcity and unwinding of complexity could easily bring a tipping point towards significant population reduction over a relatively short period of time; while ironically, at the same time, allowing most people a somewhat normal life not characterized by constant war or famine; but instead simply defined by higher general mortality rates which are perceived as a new normal.

An 8 fold increase in the number of people dying every year would create a net population decrease of about 3% per year even if current birthrates continued unabated. At a 3% rate of decrease, world population would shrink from 7.4 billion to 1 billion in about 65 years. Birthrates, though, would also likely decrease during this time due to a shrinking population base. Therefore, with fairly small increases in net mortality, the current population can drop significantly in a relatively short time. Just ask yourself: “Would my life become unbearably abnormal if instead of only 1 or 2 people close enough to effect me die each year; 8 to 16 died instead?”

Within 2–3 short generations society could be back to living a pre-industrial circa 1800 life style with a 1 billion world population similar to that era.

[ As to your use of acronyms, it is funny and charming, but without using the browser Ctrl+f function to keep track back it does become difficult to follow at times.]