If Musk really believes what he says, then he should want the entire world to Westernize.
This is because when countries Westernize the birth rate goes down.
So the answe to Musk’s fear is more Capitalism. Free people from government controls and the birth rate will drop.
This is because when countries Westernize the birth rate goes down.
I think what you are referring to as "westernize" is to adopt the long term leftist goals of "free love" (responsibility free sex), Abortion, and homosexuality. These things have decimated our population.
The left have always been Malthusians.