Most people don’t care about maintenance. They do it only when they must. So I doubt they would pay a penny extra for accurate forecasts of maintenance needs. Insurers and other types of dealers might though!
But wouldn’t constantly changing road types and weather conditions create so much variable noise that trending would be sloppy?
True, but people who buy expensive cars care, which is exactly the target for such a system I imagine.
I am not a mechanic but can at least hazard a guess at what's wrong with a car from the way it sounds with reasonable confidence. I imagine a purpose build AI design by the car's manufacturer with multiple microphones in the engine compartment and around the car could gain quite a lot of insight, perhaps even outside of identifying maintenance problems simply to tune the performance of the engine, especially when combined with other sensors.
Having said that, we seem to be near the end of the line for ICE vehicles, so I wouldn't hold my breath for such a system to be developed.
One of the manifestations of "I don't care about maintenance" is taking a car to the dealer/whoever on a regular schedule without understanding what they need to actually do to the car -- which is not caring about maintenance by having someone else care.
Having a report that's quickly spit out to the mechanic about issues over the past X,000 miles so they can quickly quote to the customer before it becomes a bigger issue would be nice.
But wouldn’t constantly changing road types and weather conditions create so much variable noise that trending would be sloppy?