Let's continue this thought experiment - say with a flick of my fingers I made everyone in the world have half the money they have now - but I leave you with the same amount. So you are basically 2X richer than you were before. You say this doesn't help you at all - I think it actually increases your chances of finding housing, finding a mate, getting healthcare etc. Your material well being is established relative to others. If we expand the neighborhood example further - to city or country, it is obvious why the amount others have relative to you matters. In a world of infinite resources envy doesn't make sense, but in our world resources are limited.