A few reasons: Ethernet electrical is more expensive and ethernet drivers are bigger code size then CAN, and more complex (buggier, you have a lot more buffers

A few reasons: Ethernet electrical is more expensive and ethernet drivers are bigger code size then CAN, and more complex (buggier, you have a lot more buffers and way more state to manage with ethernet versus CAN). Plus CANFD can accommodate different frequencies, so cheaper hardware can participate on the same bus. This may change over time as larger cores are used (Renesas comes to mind) and bigger ethernet stacks that are already scrutinized can be shoehorned in.