You got me till this point, and you prove we should be cautious about such tech. I live in one of the richest cities in the world (certainly one of most expensive), and the amount of 10+ year old cars is huge. Go to country side, and they become majority, with many clocking 15+ years.
For physical mirror to fail, you need to break it or completely lose it, and then its obvious whats the situation. Electronics have more components that can fail, and as an IT guy, I know what can will eventually fail (ie how many digital cameras work flawlessly after 10 years of daily use?). Last thing I need is to have an potentially unreliable critical safety feature in the car.