I recall reading something in the 70’s about the actual Colonel Sanders trying out the fare at one of the restaurants bearing his name (which he had already sold out to Heublein, years earlier), and declaring it “The worst chicken I ever tasted.”
I can’t remember it exactly, but there may have been some stipulation in his will that the restaurant chain would relinquish use of the original restaurant name after his death, hence the changing to KFC.
This could be crap, but I seem to remember something along these lines.