No. There are so many considerations to factor in. For one, you have many volume systems managing many different audio sources. Ringtone from plugged in iPhone via wire (maybe passenger's iPhone), ringtone from the driver's phone connected over bluetooth to Tesla's software, there's Siri's separate volume control, Tesla's navigation voice has a separate volume control than Apple's navigation voice, Tesla's media player volume, there's Apple's CarPlay music volume, every CarPlay app has its own volume control, etc... how does the user change each of these in an intuitive way if both systems are being used simultaneously? When you scroll down on the left scrollwheel, does it control Tesla's volume or Apple's volume if both are playing sound at the same time?
That's just one of MANY issues you'll encounter in implementing CarPlay on top of Tesla's current system.