Already there have been issues with manufacturers trying to patch mechanical things through software because it's much cheaper.
One example I am familiar with because of knowing some drivers, is a patch that was applied to some models of the Jeep Grand Cherokee because the electronically actuated transfer case (the system that manages the 4wd) was not always fully engaging and the vehicle could roll in park. The patch was to modify the settings in software to make sure the system was engaged instead of changing out components ... however this caused all manner of problems with some systems that had been fully operational but perhaps slightly out of spec (can't get a straight answer from the factory). Hence people's 4W Low range would periodically disable and go into limp mode, requiring a visit to the dealer. Dealers would replace circuit boards... sometimes it would work, sometimes the same problem would occur later with no predictable pattern. Some people had gone back multiple times.
There has developed a 'black market' in circuit boards from junkyards which have never been patched (once it's patched, it appears impossible for users to reset it and the dealers can't or won't).
My wife's older model GC is purely mechanical. Sure it takes a little more effort to engage the gears, but at 20 years of age and well over 200K miles, there are none of those problems.
The problem in the industry as a whole is that all sorts of things that should be left mechanical have been converted into a complex array of sensors and actuators (who on earth needs electronic door latches? What happens if you get caught in a flood?). Failures of a circuit board are difficult to diagnose and astonishingly expensive to replace (repair is not an option). Cars built around touch screens become a real problem when the screens fail, and replacement is ridiculous. I am not so much worried about hacking, but expense of repair is a serious concern with aging.
-- FORTRAN manual for Xerox Computers --