It's more than a stretch to suggest "many disasters," which is a trumpian way of inference that fiats the imaginary world into a non-specific pseudo-number. The fact is, structural failures are exceedingly rare, and typically have complex reasons, rather than a defective component or bolt.
The Partnair 394 flight cited above is such an example.
The information provided about the KC-135 does not give any reason to suspect the "tails will fall off." The fleet grounding is due to a "non-conforming part." In aviation, we see this all the time. A part may be non-conforming due to an upgrade, AD, recall of a part, or any number of reasons, including the common service-difficulty report. The SDR is simply a means of mechanics submitting their findings during maintenance or inspections, and when a common thread emerges, SDR's often become the basis of airworthiness directives, or in USAF parlance, technical orders. The finding of a part that is not in compliance does not mean that the "tail will fall off," nor does it indicate that the aircraft is unsafe. It means that the part has been deemed in need of replacement, inspection, modification, or some other means.
Non-compliant parts may simply require a visual inspection to make them compliant with a technical order, AD, service bulletin, etc. They may require replacement, marking, re-torquing, safety-wiring, painting, stripping, dye-penetrant inspection, x-raying, or any number of other specified corrective actions that might include replacement with an updated part, removal for inspection of the surrounding surface, before replacement, etc.
Some years ago, the most egregious abuser of unapproved parts, it turned out, was the FAA, which was operating it's fleet of aircraft with a fairly high number of unapproved parts, legally in public-use aircraft. Go figure. Even so, we didn't see them dropping out of the sky, or the tails falling off. Fox news has married a reference to a "non-compiant part" with images of impending disaster and drama. It's quite a leap to suggest that the fleet is grounded for fear of "the tail falling off."