You don't have to have high birth rates in a society, and you can have high death rates. What you need to focus on is the GBRDR (Genius Birth to Retard Death Ratio).
And no, it's not about meeting replacement quotas you fucking mental cops; it's about whether or not you can produce quality births and max out culling deaths - in a sense, how many baby geniuses are you making compared to the number of Darwin Awards you are handing out. That's eugenics. If you create 2 geniuses for every 4 DA's handed out to morons who play too close to the stairs, you are on a decent trajectory of honing your population efficiently.
A negative example of this is India: too many retards being born and not enough retards dying fast enough. (They clearly need more industrial hazards and trains.)
White societies, during the downslope of the industrial age, naturally were having less children, while intelligent people were breeding and dumb people were driving off cliffs. We had a decent trajectory but ofcourse Capitalism needed more retards.
The whole modern world revolves around retard slave labour. So, the next time you hear some life-threateningly dumb shit from someone, don't correct them, just go have another kid and Nature will fix the rest.