>Why does it need to be a factory Bluetooth system?
Why do i need to get RAM upgrades from Apple? Storage upgrades? CPU? battery?
Why cant i just get a third party magsafe charger?
Because Apple's ethos says that you do it right the first time or you live with the consequences (or live with our prices for upgrades) - the equivalent of which would be insisting on a factory bluetooth system rather than getting a third party device.
Of course there are numerous benefits to going with third party/aftermarket devices. If Apple is counting on its users doing that, then it represents a major cultural shift from Apple.
A Bluetooth+USB+AUX deck from a brand like Pioneer or Alpine is about $100USD. Yes, it sucks to spend more money, but you also get Bluetooth calling, proper audio format support (does your Chevy so OGG?) and even support for apps like Pandora sometimes. Worth getting _without_ even having an iPhone, for me at least.