Actually, he did invent the way to cook fried chicken in minutes and make it "fast food" (the idea of using a pressure cooker to deep fry was insane at the time as it could easily explode and cause a grease fire. Also, his protege was Dave Thomas, of Wendy's fame, who invented the drive thru.
The key to the KFC success was his ability to franchise his operation because his cooking method and recipe was easily replicated. He could make the product at scale so to speak.
NNVC has not been able to verify replicated batches at ANY scale. Remember when someone said, years ago, that it was an issue of physics?
Harlan used physics to change the cooking time of fried chicken. NNVC can not figure out how to get past this issue with duplicate batch manufacturing.
Sorry, can't sell what you can't test, can't test what you can't make (consistently).