I am a game maker by heart, and got in and out of the game industry multiple times, and I keep in touch with some people (ranging from the nobodies that do important work, like Dice and Maxis engineers, to sometimes having a facebook chat with a celebrity, like John Romero)

One thing that is common, is that everyone that knows how the game industry work, always keep pointing to Zynga that they are doing it wrong, but they don't change their ways, and keep doing it.

Yes, game industry IS hit driven, and this does lead to some problems (example: Maxis was VC funded, investors were expecting their growth to be stable, not a roller coaster, after the massive hit that was SimCity 2000, they had no time to outsell SimCity 2000 the following year to keep a growth pattern, VC didn't understood that and the end result was them being sold to EA). But even then, on long term is obvious that a company experience and solidity is more important, for example Bethesda, that uses the terrible and buggy engine Gamebryo, although I am one of the voices that keep asking them to change, I suspect the reason why they can crank games with similar quality every time, is BECAUSE they never changed their tools, and make all games similar to each other. Another RPG example is Obsidian, that for each game used wildly different tech, yet all their games are known to have a certain baseline quality that came with experience. Or for a mobile game company, Toca Boca, all their games have a distinct style of theirs, and they have a clear process on how games are created.

Zynga got one part right, that is to "fix" the hit driven problem by having some stability with their "average" releases, the part they got wrong is that they do that by just copying everyone else games, and copies rarely do great, specially in time consuming games.

When WoW appeared, and MMORPG making became a mania like tulip-mania, with investors throwing money at MMORPG companies with little thinking, I warned lots of people that making a WoW copy would never work, WoW is a time consuming game, if you make a clone, why the person would play the clone? a WoW fan will keep playing WoW, and someone that don't like WoW, won't play the clone.

Every single company I knew, that attempted to make a MMORPG after seeing WoW success (instead of making the game a MMORPG because it made sense) was a failure, I know investors that lost millions with this, and I know people that accepted a proposal I vehemently reject that got problems too. (one company approached me, and asked me to drop out of college to join their MMORPG team, the company owners visited Blizzard headquarters, were mesmerized, and wanted to copy it, but doing a christian MMORPG, I flat out refused, the company somehow went bankrupt only 3 months later).

Zynga needs to start doing serious game R&D (instead of making lots of clones), and also find their own style of games to create consistently, and find their average revenue to size the company according to it...

If you have a hit, just store the cash, many, many game companies of all sizes learned the hard way that growing after a hit can result in you having to be forcefully shrink again to pre-hit levels, usually in a painful manner that might make you lose lots of money.