Ahh yes, the elephant in the room. Nobody wants to talk about it. Go to any party and listen to anybody say how they have 4, 5 kids and people will congratulate them in happiness. Not me, I look at them and think how irresponsible they are.
Sure 11 billion people would probably be fine if people lived off growing veggies in their backyard and raised chickens and rabbits. But this is 2021, and each one of us have a gigantic footprint on the planet, with our ipads, flights, gadgets, clothes, copious amounts of food, etc.
I would guess to say that even 3 billion would be probably more than the ideal number, considering the amount of stuff we need.
I suspect the planet at some point will remind us of what are continue to ignore.