Pretty sure the actual solution to this one is going to be increasing automation leading to reduced working hours and thus more time. Some economic reform will also be necessary at some point.

Let's be real though, every other animal experiences population fluctuations due to environmental pressures. We probably can't be the only exception to that, where we only ever grow or remain steady, that's just not practical. If the economy requires it, then the economy is what will have to change at some point, by necessity.