[theincredulousk]

Having single-pair vs. cat5 is kind of a bonus, for wiring simplicity and weight. I could also see the power delivery part being useful for things like sensors and other oddly placed/small powered devices.

The main benefit is Ethernet. It has already started, but in the next few model years of cars, there is a large transition happening from CAN -> Ethernet as the primary communication bus. The simplest reason for that is software + bandwidth + integration.

To implement semantics like an RPC call across two modules in car via CAN, it is kind of ugly and almost always results in awkward software interfaces and extremely inflexible implementations. Whereas with Ethernet now you can do something like use gRPC and protobufs, which is entirely flexible and results in well-defined/formed software interfaces. CAN will still be used for a while for what it is best at: low-level, reliable, low-bandwidth chatty data interfaces that make sense for electro-mechanical parts - especially those that don't have (or need) anything more than a very bare-bones microcontroller. Cost is still a huge factor in automotive design, because a $1 difference x 1 million cars blah blah it makes a difference.

Bandwidth is obvious. CAN can't do video, and in practice audio either (although theoretically possible I guess). Cars have lots of audio and video devices now, and it is unnecessarily complicated to always have command/control and media data on separate buses. Imagine if your computer used one physical network interface for HTTP requests and another interface for streaming video. Sure it'd work fine but you'd have a bunch of extra cables, ports, hardware, and software complexity to make it work.