Presumably so you can reuse all of your existing CAN car parts. Even the lights are on CAN now, it's going to be a lot of stuff to transition to Ethernet. And

Presumably so you can reuse all of your existing CAN car parts. Even the lights are on CAN now, it's going to be a lot of stuff to transition to Ethernet. And you have thieves stealing cars by hacking into the easily-accessible car light CAN bus - a CAN network switch could also act as a firewall to fix those thefts without re-engineering every single part. It makes sense for Tesla since they're more vertically integrated but other car manufacturers seem more "parts bin" and having to migrate your whole car over to a new architecture will limit the parts you can use massively until the whole industry switches.