What is the reasoning for the plateau, though?
declining birth rates in developing countries.
That seems like a pretty big leap in logic to me, but I hope they are right.
Declining birth rates in developed countries is a fact. If an country is developing, its a pretty safe bet its birth rate will decline.
I'm not saying it's not going to happen. I'm just saying that a model that relies on a change in human behavior seems a whole lot less reliable than a model that relies on a proven scientific theory being accurate.
Can you give an example of a developing country that is going to be fully developed in 30 years?