It's crazy to me that this is possible in the first place. Standard practice is to have a fleet of test vehicles that are effectively production except in an early release group. Or, you know, having an A/B boot partition scheme with a watchdog. Things that have been around for decades at this point. Disclaimer: Former Googler, Worked closely with Automotive.
The code went through early release tests successfully; the problem came with how it was more broadly released. They should have had further staging of the rollout (randomizing when it is offered to users).
Edit: Also, why the heck isn't the entertainment system completely air gapped from the software running the car?