My 2000 Tacoma, 2001 BMW 335, 2007 Tundra, 2008 Fusion, 2009 Jetta, and 2013 Fusion all had this feature. I miss not having to constantly adjust the volume form highway levels when I pull into my driveway/office.
Okay, I am convinced. I find some of the gaps within a manufacturer's model lines a bit wierd, but don't doubt the reality. With the Tesla already having a microphone in the passenger compartment and a electronic volume control, you would think that this could largely if not entirely be implemented through software.