That video is terrible. America has been becoming much more health conscious over the last couple decades, so it's no wonder a mediocre fast food joint that focuses on serving up one of the most unhealthy foods in existence is suffering. The other problems, such as cleanliness and prices, are symptoms of the overall decline. The Chick-fil-a comparison is awful, because it serves a vastly different product than KFC (chicken sandwiches compared to buckets of fried chicken), and Chick-fil-a has the novelty and growth factor going for it. It's a lot easier to be successful when you can still open new stores in new places. KFC has been around for so long they've basically blanketed the country. This is a similar problem that McDonald's has been facing for a while.
The guy who made this video is also apparently a massive hick who has never left his podunk town. The reason KFC is popular overseas is NOT because of marketing. It's because overseas KFC is exotic. Traditional fried chicken like you find at KFC is a pretty uniquely American food. In many countries, if you want to buy fried chicken, KFC is literally your only option and it's something interesting and different. That's dramatically different than the U.S., where every little town has AT LEAST a KFC and Popeyes, not to mention mom and pop fried chicken joints.
Stupid video is stupid.