Maxis was created to produce games that were not games, and they remain doing so. Just.
Maxis create Software Toys, and that is as different as Kerplunk is from Barbie. I will explain:
In Kerplunk, the game is that you pull out sticks until the marbles fall down.
In Barbie, the game (I'd imagine) is inside your head. Barbie can be a stewardess, a shopaholic, or an abused drug-addict for all Mattel have to do with it, the game is whatever you want it to be.
(Except that the direction that Barbie and all the other previously "Imagination" toys are being corporately manipulated so that you are directed for what to do with them. But that is a seperate rant, for another time.)
Simcity, Simant, Simearth, Simlife, Simtune, Simfarm, The Sims are not about "Do This", they are about "Do what you like, here, take it, have fun. Knock yourself out". A fact that many games players and journalists have a hell of a lot of problems with. The down side to these games is the market. For the Playstation Generation, the aim is a quick fix, not a slow learning curve until you can get the hang of it and be the best (Although the sucess of Counterstrike proves that this method works among PC gamers), and so Maxis were bought out by Electronic Arts.
Although Maxis appear to be resisting, EA have a nasty habit of making their labels keep pushing franchies until they squeek (Witness FIFA, NHL, NBA, Nascar et. al.). I'm hoping that the great plans made for Simcity 3000 (which included full 3D) will be levered into 4000 (They are promising full 3D for simsville) and that the next Maxis games will not be Disneyized versions of previous titles (like Theme Park Worlds was).
Maxis was founded by Will Wright and a coworker when nobody else would publish his games because they didn't see a market. To see it swallowed completely by a Global Megacorperation would be a crying shame.