Yah, I know from friends at ford and vw that there's still vxworks and qnx, but even there, good grief, a-b with confirmed boot is about as basic as you can get.
I confess I've seen incredible sloppiness about when a confirmation is done (too early, including in the initial init stages which is way too soon) and watchdogs (spawn off a process that has a while loop stroking the wd - just absolutely pointless).