The show was probably greenlit based on a meme that gained popularity, and how the fans talked about the movies. I think before the first series came out, the people involved talked about how popular Karate Kid still was, which got them thinking about bringing it back.
Some fans intentionally talked about the happenings in Karate Kid as if they were real, and Karate Kid was a documentary. It's funny. And the show has taken that premise, so everybody in the show takes the whole Miyagi Do, Cobra Kai, Karate thing super seriously, which makes it even more enjoyable. They commit 100% to the whole mythos.
Chat on Imdb boards, and other places on the internet, the video below was the inciting incident which gained traction, bringing a lot more fans out of the woodwork.
That's why we had Jonny as the protagonist in the beginning, and Larusso was a dick. It wouldn't have worked if we didn't have Jonny, and his side of the story. Nobody wanted a Larusso story again, the fans wanted Jonny.
Daniel was the real bully.