SW is first and foremost a story...Tolkien made LOTR a great story above all before any kind of marketing happened.
Lucas did the first one and then the marketing set in. I think the two are comparable in what to do and what not to do with creative fiction.
Tolkien wrote the entire LOTR trilogy between 1937 and 1949 and it was published between 1954 and 1955. So the story was completely finished when it was finally published and any kind of marketing afterwards didn't affect the way the story was written. SW was an ongoing thing and I do believe marketing played a role....especially in the prequels.