I don't disagree with this either. Capitalism requires a constant stream of new people to operate effectively to increase labor output. This is the system we've been dependent on. We wouldn't need a >2.5 birthrate to maintain all of our water, electrical, and communication systems.
I hate the type of people that hammer the idea that society needs to double or triple the birthrate (Elon Musk), but as it currently stands, countries like South Korea, Japan, USA, China, and Germany risk extinction or economic collapse in 4-5 generations if the birth rate doesn't rise or the way we guarantee welfare doesn't change.
The risk is a quantifiable 0.0%? I find that hard to believe. I think the current trends suggest there is a risk that continued environmental destruction could annihilate society.