I think it's mostly because of how aggressive and one-way tesla is. My 6-year-old volt can probably get firmware updates over the air, but I've never stepped into my car to discover that the emergency blinkers are now hidden, the windshield wipers are now on the other side of the column, and my battery has been limited to only 60% of what I bought because telsa flipped the wrong bit 4 years ago and two owners back and has decided to "remedy" my experience.