I think getting nailed by an old driver in the road who is too senile to be driving is a lot less likely than getting nailed by someone pulling out of/into a driveway who didn't see you. The former is a pretty small segment of drivers, comparatively speaking... the latter can happen to anyone, even good drivers.

I think this because as someone who is probably more conscientious than your average driver when it comes to looking out for cyclists, I've hit a sidewalk cyclist. Blind driveway, couldn't see them in time (this was with a slow foot-on-the-brake roll). Luckily, since I was going so slowly, I just knocked her over and she wasn't hurt. Had I not been so cautious, she could've ended up under my wheels.