I have a theory (but not the education or intellect to properly express it) that in order for for some people to capture the benefits (i.e. strength and to a secondary degree hypertrophy) the body MUST be trained using "as much muscle mass as possible over the longest practical range of motion;" That without doing it that way, the nervous system and spinal column are not adequately stressed to signal that changes and growth are required.
Obviously, there are some bodybuilder types and outliers who can induce strength and hypertrophy changes with highly isolated movements. But if you're located anywhere on the curve other than this outlying tail, you're going to need to use the compounds and the SS method to realize adaptations. What also injects noise into the system - is that one can induce soreness with single joint machine exercises, which causes people to believe that meaningful growth shall follow. But unless you are one of the aforementioned outliers, that ain't going to happen.
Simplicity of the program is a feature, not a bug. Brilliant analogy to running, Rip. Although I think I remember reading in "Portrait of the Artist as a Young Man" that certain track athletes train by running with their arms held tightly at their side, not pumping them up and down. Sort of like benching with the feet up (which is a silly practice). I don't know if track athletes still do any stiff armed sprint training anymore.
Anyway, I know you're not "broad" casting the message, but it may help penetrate the minds of the "broad" to point out that running, too, is systemic.