And it all started with Jar Jar Binks.
See Post 58. It started with the second production they made (1978). Jar Jar Binks was pathetic but nowhere near as pathetic as the any part of the Holiday Special.
Teddy Bears. That stupid Teddy Bear movie destroyed any further consideration of Star Wars as a serious science fiction story.
There is an excellent youtube video called "Star Wars: Saved by the Edit." It makes a very good case that Lucas is an idiot, and that his wife at the time was the real brains that made Star Wars successful.
I will point out that she was with him during the first and second movies, but she was gone by the time that stupid Teddy Bear movie came out.