Are loose teeth in a saw blade a safety concern?
Loose teeth on a modern table saw blade are indeed a thing to be concerned about. It would be anybody's guess as to where the loose tooth would fly if it came off the blade. As many readers here may know the most popular blades in use today are the type with carbide tips bonded to the tooth cutouts on a blade core.

It is possible that there is a history of table saw safety over many years that has contributed to the current body of knowledge, articles and videos. Historically the saw blades in use twenty or thirty years ago were much more likely to be steel blades with teeth that were sharpened and set with alternate facing cutting edges that were bent slightly in each direction from the plane of the blade body. It is much less likely that a tooth on a blade would come flying off when the teeth are all cut and formed from the core material of the blade. So in the past it was less likely that saw blade destruction would be stressed in any particular way in safety information.

It is also true that warnings about trying to use blades that are dull and worn would have been more prevalent. The modern carbide tipped saw blades in common use today stay sharp much longer. And even if they do become slightly dull the integral design of the blades upon which the carbide tips are mounted prevents a lot of the binding of the saw blade in the kerf that is experienced with an all steel saw blade when the teeth have lost most of their set.