For a virtual in-game economy to maintain economic equilibrium — the relative stability of its core currency and items — it must balance the rate of asset issuance with the rate of asset consumption/demand. Stuff in ~= Stuff out. To do this it has a couple of options:Continuously grow the rate of growth of new users to allow older players to sell to newer players.Continuously introduce newer, harder, and more resource-intensive end-game content for existing players to expend more resources.Ba...