Just a bit of an aside, It seems like a lot of people get into the mindset that when we think of going from 3 billion to 12 billion people, the new 9 billion are just sitting doing nothing and the existing 3 are all still the ones doing everything.

With an extra 9billion people we should see an increased velocity in all areas of life as well. Innovation everywhere will increase, solutions for "scaling anything" will advance, food production, energy production, construction projects, all also increase..