Things were so much simpler when the only problems that could cause unintended acceleration were mechanical in nature. A broken return spring, seized linkage, etc. My daily driver has a mechanical throttle (although it is electronically fuel-injected), and honestly I can't see much point in "drive-by-wire" for cars.
But, on the other hand, even despite so many possible bugs, AFAIK no one has been able to demonstrate one instance of unintended acceleration even with extensive testing.
Drive-by-wire is good for a lot of efficiency technologies because it enables the elimination of the throttle plate, and therefore of many kinds of throttling losses (see MultiAir, ValveTronic, ValveMatic, etc.). It also enables simpler cruise control and traction/stability control systems. The addition of computers to cars is mostly a plus (IMO) but the hidden complexity is frightening to say the least.
Have you never encountered such a bug? It isn't difficult to understand how hard a bug might be to track down when it only affects such a small subset of your users and only under specific circumstances. It is the dreaded Heisenbug
But, on the other hand, even despite so many possible bugs, AFAIK no one has been able to demonstrate one instance of unintended acceleration even with extensive testing.