The ultimate carrying capacity of the Earth can increase far beyond what it is now, and here is one way it might happen: Imagine a world where there are fewer roads but they are double or triple in width, and nobody actually has to go anywhere on a daily basis. Everyone is on the internet. Every community contains a small automated manufacturing facility taking care of most needs (The tech for this exists btw.). Farming and other repetitive tasks are handled by artificial intelligence robots. Food and medicine become freely available, limited only by the incredible amounts of energy our sun pumps out every day. What would be the earth's carrying capacity then?