You raise a good point, and I believe you are correct. The one issue I see here is typical humanity - people let their cars go without maintenance until they are too dangerous too drive. I doubt the automated systems will detect loose or broken sway bar links, worn tires, loose ball joints, worn tie rod ends, and so forth. Or maybe they will and prevent the car from being used, but if so, people will be furious that they actually have to fix their cars instead of driving their dangerous sh!t boxes on same roads as me.
If they don't already have automated systems to monitor key mechanics, they will.
You have to remember that adoption of this technology won't be instant. Right now they have around a dozen test vehicles that have driven around 300,000 miles. They will take the feedback from those miles and consider that in fielding maybe 20 or 30 initial "real" vehicles, then gradually expand things.
A lot of maintenance issues on these cars won't be that much different from those of regular vehicles. Bad problems usually make a noise.