For what it's worth, in the last few years I can only remember two tires that failed catastrophically. Both were front tires, and both tore at the sidewall-bead interface. Luckily neither one caused a crash, but it's still scary. One was a fairly cheap Michelin, the other a Panaracer Col-de-la-vie 650b. And both were basically new tires, less than a month old, and neither showed any wear or signs of other damage.
That sort of damage, if it is where the plies wrap around the bead, is often caused by the pinching action of tire levers on the casing fabric.
The bead under tension is much like a hard edge having a small radius, thus able to concentrate force at a tangent contact area of the bead, thus potentially severing the fibers of the casing, with resulting separation of the casing from the bead under inflation pressure tension.
Even when using a sliding motion with a tire iron along the rim and tire bead, I've seen the cloth chafer strip shear right off, and have seen the rubber peel away on tires that have no cloth chafer strip along the bead edge. An aged tire will be particularly vulnerable to such damage.