Well eventually the population gets to 4x what it is today, and then you are going to be using all of the available land to grow plant based food for everyone.

Well eventually the population gets to 4x what it is today, and then you are going to be using all of the available land to grow plant based food for everyone. So now your choice is limit reproduction or starve, so obviously you're going to choose to limit reproduction. It's inevitable, so might as well do it at a point where everyone doesn't have to eat nothing but rice and beans.