Do you own the software and firmware in your car?
The navigation system might use Google Maps and requires an internet connection to function. The manufacturer may decide to no longer want to pay for Google's license and therefore disables all software - including software running the ignition, engine management, the speedometer, the center console - on the car with a momentary notice. The car becomes undrivable as a result.
Should this be legal? You didn't own the software after all.