I've been also thinking about this. Would make perfect sense actually. Capitalism needs a certain rate of unemployment to drive down wages but with too many unemployed there arises a risk of riots and eventually even revolt. Seeing as how we're well on our way to mass automation of menial and analysis desk jobs unemployment will inevitably rise. I'm sure some concerned persons have made their calculations regarding both the sweet spot of the rate of unemployment and the projected layoffs and this could have called them into action. Thus they kill 3 birds with one stone: getting rid of the excess unemployed, getting rid of the elderly to right back the demographic pyramid on which pensions are built and getting rid of those with health conditions - relieving the health insurance industry. A significant 4th "bird" is somewhat scaling back the population to get more in line with the carrying capacity of the earth. We know that a well off person in the West produces at least 100 times more emissions than a regular person in the developing world, and for western billionaires this number skews even higher, but since the lives of the (western) bourgeoisie are sacrosanct something else needs to give and this something else are the lives of the poors. China in this scenario would be used as a diversion tactic, so the western populace doesn't get too many conspiratorial ideas about our bourgeoisie.