Given that, I hardly think that 'decoy sims' are much of a stretch.
It is everyone's information that they value, not that one guy who goes to the trouble of killing the radio.
The only reason a decoy sim is going a bit far to believe, is because it wouldn't actually work. It wouldn't actually fool anyone and would just look bad when the first reviewer pointed it out a year before the car is even available for sale. If it weren't for that, we already have countless example proofs that a company will do literally anything if it will work merely 1% more than whatever it costs. Including car makers obfuscating and even flat out lying about their various connections.
What do they get out of it? data & control, same as ever.