> They all follow the same model of "build a good multiplayer experience and "support it" perpetually by squeezing as much revenue as you can from your users".

It's a viable business model and it allows players to enjoy the game for many years to come. What bothers me a little is that these revenue extracting schemes are usually very complicated and are probably complicated because it allows them to extract as much money as possible from a small subset of players. Like casino's and mobile games.