If the caliper was sticking then the pads may have been rubbing and
they could wear out rather quickly. Once worn, you would have metal
on the caliper rubbing the rotor and the rotor's life would then be
measured in seconds (that was probably the teeth crunching sound).
Caliper failure is not unheard of but not all that common. But,
calipers are never replaced as part of maintenance and failure is
low enough that I doubt anyone would replace them as a preventive
measure (if a dealer did people would scream that they were being
ripped-off for unneeded parts). It really was not a predictable or
easily preventable event.