good thread title and idea. yes, the world can be a 'surplus' in a number of ways. economies do not have to grow endlessly. i think there will be many pockets or small areas of self-sufficiency in all the vital goods and services, linked by mutual long distance trade, after going through a long spell of specialisation of various large nations in certain goods and services.
KIyer is right. Economic growth is necessary only if there is population growth. If we reduce the population, living standards will increase without ANY economic growth as long as the productivity is not simply given to the elites. So social democracy (which simply puts LIMITS on capitalism) plus population reduction is the key. Nor will there be any "serfs" in the future world. The most unskilled jobs will be done by robots.