Apple's In-Car Siri Integration Hits a Roadblock | Autopia | Wired.com In essence, long product lead times and the fact that most voice recognition controls default to voice recognition embedded in the radio are getting in the way. Note GM's approach was aimed at lower end cars and therefore assumes people relying on their phones rather than on high end radios.
The other thing that seems to be happening is that some car makers are giving developers a sandbox to play in with respect to apps, while others (Toyota) seem to be taking a very restrictive approach. I can understand taking a somewhat curated approach like Apple, but Toyota is never going to do anything worthwhile in this evolving car app and tech space unless they are willing to open up and get out of the way to some extent.
