Fun fact: There are people who enjoy the Sequel trilogy and are grateful for these movies. If you don't enjoy the ST, that's perfectly fine. But stating that the ST have no reason to exist like it's a fact doesn't make much sense. To plenty of people, those movies made sense to the previous storyline and to the continuation of the saga overall. So, your conclusion that "Star Wars should have ended at Episode III" seems like a subjective argument, not an objective one.
Regarding George Lucas saying that SW was solely about Anakin/Vader's fall doesn't seem to make much sense, either, seeing that Lucas apparently planned on making a Sequel trilogy himself. So, really, I'd disagree saying that there shouldn't have been a ST to begin with. I think it's the execution rather than the idea that bothers most SW-fans. I've seen plenty of comments where SW-fans said that the film adaption of the Legends Thrawn-trilogy would have been better. So, although there is probably a part of fans who think there shouldn't have been sequels to begin with, I think most of those who are discontent about the actual ST bemoan the execution, not the idea of a ST.
And I personally enjoyed "Solo" and "Rogue One", so that's another reason I'd disagree with you that there shouldn't have been any further SW-movies