No, you and Musk are wrong. The population peak was fueled by our active exploitation of fossil fuels. As the ERoIE is in decline and only fools bet on future promises of sustainable energy equivalence, the population decrease must follow this energy curve down in parallel.

Plot those two curves and only then do you have the complet picture.

Because then you will see that at some point the energy curve will flatten to it's new equilibrium. Only when nearing this flexure point and not before will it be safe for humanity to start re-breeding at replacement rates of 2,0-2,1.

Hoping that the energy descending rate is not steeper than 1,6-1,7, we could safely reach these new steady state carrying capacity levels in about 200 years. At roughly 1/4-1/5 of our current numbers.

The more we deviate from this descending energy curve the more people will be forced into famine, droughts and war. In short simply pushed off the population curve to auto-correct it.