As all cars become integrated with software management system to control almost every aspect of the car, things change each year. You may have a perfectly functioning car one day, and experience something very different after a simple upgrade.
Mechanical deficiencies are normally addressed within the year a car is released. Software however, can easily be compromised long after by a misplaced line of code, or a test line left in place at each upgrade This happens now, on everything from PCs and phones to aircraft. Cars will be no different. Expect in the future that the upgrades will be delivered directly to the vehicles component through satellite or mobile devices.
Another future issue then would be that cars are becoming integrated with communication networks and mobile devices and are also subject to malware or viruses just like any other digital device. Imagine the fun.
So, I would not lump software in with all mechanical issues because they can happen much later in a cars lifespan.
