The burden of proof is, unfortunately, solely on the person making an assertion.Do you have any existing evidence to suggest otherwise? that is the real question.
I agree with all of this; I was more specifically questioning this claim:senescence in the growing shoots or tips plants is basic botany kid !! (see our galleries if you seek images)
likewise plants are susceptible to viruses and pathogens, every time plant tissue is scared , cut , and damaged during propagation methods. Thus exposing internal plant cells to airborne pathogens and knife borne bacterium, and anything you have up your nose. This is the reason why professional growers use sterilised blades when taking 100s of clones in the garden.
Clones definitely get "played-out" with age,,, as do mother plants.
Either way, thanks for sharing your thoughts!