To a certain extent, this comes from historically creating safety-critical software which is an entirely different process compared to what is done for web apps etc. I don't think Tesla are as robust with their development processes, but they are able to make up for it with over-the-air updates.

I have worked for nuclear domain and for aeronautical domain. These are domains where safety critical software is understood. AFAIK, software is not understood in car industry. It looks like they compensate poor programming by more testing.

You should see Toyota entune. New RAV4 SE, awesome car, tons of safety and sensors. Garbage software.

I think car makes just don't realize how big of a role, great software plays in how you feel about a car.