These cars run in the millions in production numbers and are driven everyday, all day, by various types of drivers in various conditions. Where's the big firmware mess? Ignoring the limited case of this Prius issue, which seems to have a lot to do with floormats being stuck to the accelerator, I'm just not seeing it.
I think there's a problem of visibility here. If you've worked in, say, fast food, you might not want to ever eat it. Software is the same thing. You get to see how the sausage is made. That doesn't mean that the sausage is unsafe. Or that older methods, you didn't witness or were part of, were better.
You drive the rear wheel drive V8 that weighs 2x my car's weight and I'll drive mine with front drive, ABS, traction control, and incredible MPG. There are a lot of reasons to own a classic car, but safety and efficiency aren't those reasons.