One aspect you aren't twigging on is that the monetization strategy is tied to the game design. Even if every game, on average, took in the same amount of money once it hits critical mass, players aren't going to invest in games that their friends aren't playing, so splitting the audience up hurts Zynga. Their growth strategy was one of complete content saturation using fast-follow tactics. "If they aren't playing Zynga game X, then we want to make sure the other game they will be playing will be Zynga game Y instead." This worked during the explosive growth period, but it's very wasteful now growth is slowing or even shrinking (I'd need to look at the numbers more closely).
As was also mentioned elsewhere, players are always hungry for new items, and my guess is that Zynga has plenty of metrics to indicate that new items is where the money goes (a hefty dose of behavioral economics like scarcity is used on those ones). Simply leaving a game open, or closing it to new players, is probably leaving money on the table. That said, I think there's a big risk in teaching players that their virtual items really do just disappear into the ether.
My guess is it's the right move for Zynga to make, but Indiana Jones and Mafia Wars 2 is a huge blow to them. They were flagship products, and both of them are only a year or so old.
As was also mentioned elsewhere, players are always hungry for new items, and my guess is that Zynga has plenty of metrics to indicate that new items is where the money goes (a hefty dose of behavioral economics like scarcity is used on those ones). Simply leaving a game open, or closing it to new players, is probably leaving money on the table. That said, I think there's a big risk in teaching players that their virtual items really do just disappear into the ether.
My guess is it's the right move for Zynga to make, but Indiana Jones and Mafia Wars 2 is a huge blow to them. They were flagship products, and both of them are only a year or so old.