The part about the mechanical guy being the top dogs seems more to do with the fact that a car must mechanically be safe above all else right? Like, I should be able to drive a car if the software fails. But the mechanical parts and components are the things that cannot fail or have a much lower tolerance to fail. It stems from a culture of not relying on software too much no?
There are few (no?) modern consumer vehicles that don't have safety-critical software somewhere and you couldn't legally drive any modern vehicles that don't have working software besides.
It's literally just a cultural issue that they think of themselves as car companies first, and good software culture isn't in their corporate DNA. 5-10 years ago literally no one understood that, but most executives are starting to get onboard with the need for changes and flail their way through them.