If I may, there is a solution. I am its author. In it demographics would govern total output. There would be material security for all citizens of any nation that adopted this paradigm. Recent history has demonstrated that, overall, people with material security tend to have fewer children, not more. [For the record, I do have an M.A. in economics.]

if curious: "Economic System Not the Problem" (here in Medium, but not behind the paywall)