The wealthy last century believed in eugenics. These new ideas seem like eugenics rebranded, thinking that their offspring are genetically superior to other humans
They might be right.
8 billion people and they're worried about the population? Yeah, they might be able to reproduce and take over, but they might also be victims of a crime, natural disaster or even a war. Bit selfish, eh?
EDIT: 2nd or 3rd generation "special" people often lose their drive/purpose. This would defeat their purpose.
Imagine being asked to reproduce with the same guy in various Ghislaine Maxwell photos.