ROTJ is the beginning of SW becoming too popular as Lucas tries to please everyone including little kids like me, instead of just doing what he did in ESB: Make the story he wanted and if fans come along for the ride, thats great.
If SW was just a cult hit, there wouldn't have been prequel trilogy, because it wouldn't have made huge money for Lucas. Lucas said to Charlie Rose in Sept 2004 and I will never forget this quote, "In the early 90's the marketing team at Lucasfilm presented me scenario's if I made the PT, and how much money it would make. I had to make a choice, make these three films and make enough money to never be dependent on any studio in the future, or push SW aside for good, and just make the movies I really want."
Guys, it was all about $$$$$$$$$$$$$$$$$$$$$$$$, and that is why he compromised the quality of the films for short term success to get the mass audience and the little kiddies in the theaters instead of his original intended audience.