This is something I've been wondering about for a while: To what extent are our economy and stock market merely ponzi schemes that require continued population

This is something I've been wondering about for a while: To what extent are our economy and stock market merely ponzi schemes that require continued population expansion? If growth slows down/reverses/stops, is the era of easy profits finished? Or in other words, what will happen to my total-market ETF shares if population growth slows/stops? Is this an argument for investment in the developing world?