Brake-by-wire sounds scary. In my current, recent-ish car, you can still control it - with more effort - if engine and/or electrics are out. I've had the experience of driving home with a suddenly failed alternator, watching one system after another report offline, until as I turned into my street, the power steering went too. But I was able to safely drive it to my driveway (with 7V remaining on the battery). I'd rather that cars stay that way, and not just because I'm a grumpy old man in training.

I do wonder about ABS and always have. If ABS can make the brakes not brake even as you fully stomp the pedal - is there a reasonably conceivable failure mode that would simply prevent you from braking despite perfectly good hydraulics and a stomped pedal?