Head stay failures are the most common ones. The general point is from the top of the mast. This is due to furlers. Te oscilation of the furler causes premature breaking of the head stay. changing only the head stay in this condition is enough. The other stays are generally safe to use.
I am assuming that you are thinking of failures that occur because a toggle wasn't used at the top of the headstay. Something that every furling system manufacturer strongly recommends as far as I know.
Even a headstay without a furler should incorporate a toggle at both ends.
A furler, properly installed will not cause a headstay to prematurely fail.
The Hyde furlers did not use a head stay. The stainless swivels were basically glued/epoxied/bonded onto a solid aluminum extrusion that acted as the head stay. Some of these Hyde's had the swivels come unglued from the extrusion.
You neglect to mention that there is a stainless collar that is swaged onto the aluminum extrusion before the fitting is filled with epoxy.
I have never seen a failure of this installation.
And I've rebuilt and replace dozens of them.
The Hyde Stream Stay systems are somewhat prone to bearing failure. But it is a gross mis-characterization to say that the systems fail because of the terminals.