In the land of the blind (economics), the one eyed man is king.  So, forget everything you know (or don't know) about economics and follow some very simple math that economists (and financiers, Fed chiefs, and administration after administration) are unwilling to publicly acknowledge.  Disregard theories about ever greater production equating to economic growth...all that truly matters is the ability to consume that production (otherwise production turns into excess inventories).

Simply put, every person on earth is a unit of consumption multiplied by their income, savings, and access to and/or utilization of credit (even if it is government provided via social programs).  Thus, it is the annual change in the population (multiplied by these levers) which is the primary driver for the annual change in consumption.  But population growth among the nations with the income, savings, and access to credit has fallen in half since peaking decades ago...and growth among the all important work force is facing imminent and ongoing decline.