EA also has some history of allowing semi-independence of studios they buy out if they have enough clout and fight for it. Maxis managed to even stay in a physically different location, partly to maintain cultural independence, and partly because Will Wright didn't want to commute to Redwood City. Admittedly, being Will Wright is sort of an exceptional case when it comes to negotiating clout.
The essence of EA's management style is that they're content to leave studios on their own, so long as the studio is consistently laying golden eggs. When that studio experiences a significant failure (when, not if) EA corporate has no qualms about slicing open the goose to find out what went wrong.
They're better in this regard than they once were, because they have some level of restraint now, but the creative hit-or-bomb nature of the video game business means that eventually they eventually feel compelled to exert control over all of their acquisitions. Wright had a large degree of autonomy for a long time because he made staggeringly massive amounts of money for EA with The Sims, but it didn't protect him from being pushed out when Spore turned out to be an epic flop.
Bioware appears to be an example of that. They have changed a lot their business strategy (lots of DLC now) but their culture seems to remain the same.
