I'm not sure that I agree. EA is larger and also are known for their "always on" DRM habits. Granted, it could be that the "always on" DRM worked nicely in to Maxis's plan for a Sim City MMO, but I'm not so sure.
I would think it was Maxis' decision, not EAs. Maxis makes craploads of money and is allowed to operate however they feel is appropriate.