Worse, even the external comms systems are moving to more redundant setups to mitigate signal loss scenarios.
How well does this extend to other vehicles? No clue.
Things are changing though. Autonomous vehicles need large numbers of sensors up there anyways and you can't keep shoving everything under the cabin.
This is less of a directional shift IMO as the classic "hardware companies are bad at software" issue. There's no unsolved or novel problem in this SiriusXM vulnerability (or one from the same researcher in Hyundai/Genesis systems where they compared a JWT subject with a subject passed in the request, but stripped whitespace). There's no update-frequency or validation issue. It's just basic web application security getting neglected.