The # of workers is another contradiction of capitalism: you’re correct that they want a reserve army of labor to keep wages down, but at the same time too many people counts as a “surplus population” that can have revolutionary potential, and be a burden in innummerable ways. Capitalists either have to start wars to kill them off, resettle the ones in the core country, find ways to avoid paying for their well-being, find ways to cripple their revolutionary potential, etc.

Masses of pissed of peasants ( a “surplus population” who were becoming increasingly unnecessary in the newly industrializing periphery countries ) formed the backbone of every successful communist movement in the 20th century. The malthusians and neo-malthusians like Bill Gates ( as well as first world anti-natalists, pushing the language of choice and “empowerment” and scaremongering about third world overpopulation just like any white supremacist ) are scheming to find ways to slow down birth rates in poorer countries because of this: they’re very aware of the revolutionary potential of the third world, and want to find ways to tune the population numbers to desired levels.