Just think of all the integration programming jobs that will be preserved! All of the pointless conference calls and GoToMeetings scheduled weeks in advance between developers and project managers and teams on the other side of the world because someone made a typo in an API specification that could have easily been cleared up in a two-second email.
Good times ahead! The hardware stacks will all likely be different too, so gravy train for all the HW and systems folks too. dozens of companies all re-inventing the same thing is why tech still has full employment.
Actually, the hardware guys already have it solved. We already know how to do bus arbitration, and cars are like little buses.
CANbus could work, and it's already used in the automotive world. It's nice because the higher-priority bus driver is not delayed. Unfortunately, the lower priority one gets run over. Might have to work on that.