>But must this happen? Can't the developed countries perhaps pass their developed traits on to other up-and-coming countries to also stabilize and then slow their growth, and eventually we arrive at a stable and peaked, or perhaps smaller global pop the planet can actually more easily sustain with a sensible energy mix?

Not if you promise the productivity of people in future generations to the current generation, but then find out the productivity of people in future generations falls short (perhaps due to insufficient people).