> Maybe I'm making a bad assumption but it seems unlikely these folks are the idle rich spending their spare thousands on gold bars.

Having worked at a mobile games company: they actually are! We were heavily propped up by, among other things, Saudi oil tycoons trying to out-spend their (equally-rich) friends in cash-shop items, for the sake of being on the team with the highest power-level. We were effectively a virtual arms dealer selling to both sides of each little status-war between these folks. We considered them so important to our business-model that we took their likes and dislikes heavily into account in deciding which new games to make.