Fewer people means the economy and finance will shrink. This is not something our system is designed - almost all economic models need constant growth, which as

Fewer people means the economy and finance will shrink. This is not something our system is designed - almost all economic models need constant growth, which as you rightly mentioned is achieved at great cost to the environment and other species. I also feel that fewer people will also translate to fewer billionaires and newly minted rich folks and transfer some power balance to people willing to do the labor.