"we know electrical trumps mechanical more often than not"
We do? In what sense? A mechanical switch is simply a mechanically activated contact plate/circuit. That's as simple as it gets, really. Sure, you've got mechanical wear and tear, but mechanical items have progressive wear, often - their failure mode is not immediate unless it is a catastrophic failure.
Mechanical/electrical switches for ignition have one/two failure modes: your car won't start, or your car will stop. The second is drastically less likely than the first, and applies to almost every motorized vehicle, ever. It hasn't exactly been a major concern.
A simple mechanism is inherently less likely to fail than a complex one performing the same task. Good systems people know this: cyclomatic complexity is bad.
From what I'm understanding, 'switchgate' is merely the failure of the electronics associated with the mechanical switch, and circumvented safety measures.
This sounds a lot like the many lines of bullshit we've been fed by various government and corporate bodies, in the past. They're pushing this shit through regardless, using something they fucked up for an excuse to fix it with something nobody wants. (My recollection is that the 'complaints' have largely revolved around the $200+ chipped keys automotive makers have been using, after all... We don't hate the keys, we hate electronic meddling -unubtrusively- with our mechanical devices (ie cars).)
Basically, automakers just want more control of your vehicle, and the revenue stream which results from fixing it.
(Side note: Remember when they said electronics would reduce the cost and maintenance on vehicles, in the late 1980s/early 1990s? That was true, in so far as the cheap stuff that broke was often replaced. But they're replacing everything with electronics now, and so many of the things that should not be 'electronic' (ie just need a simple electrical signal to work), are.