They had two diverse paths, but apparently did not have a (reliable?) process for ensuring the backup path was functional during fail-over. I imagine there will be some soul-searching over that.

Nothing I've ever seen or experienced with FAA indicates a lack of care; the parsimonious explanation is almost always that people who care a great deal are working within complex systems that don't always have a consistent or externally legible set of priorities. Or more intuitively, the failures we see are the "acceptable" ones versus the unacceptable ones (like planes falling out of the sky).