I guess you don't know the story behind how he soled it. The way he managed finally to convince the producers to make it a movie and the fact that he created all the weird effects by his own shows that he didn't soled it because he was known of course!
You said "He wasn't known". Perhaps I don't know the story behind
how he sold it, but I do know that we was known. He was an Academy
Award nominated director, an Academy Award nominated writer and
had made a very successful movie.
The way he even got in the door to finally convince producers to make
it a movie was because he was known. Yes, the script was a hard sell,
but he was known. Which is the point of this topic.
Victor asked if a beginner has a chance selling a big budget Sci-Fi script.
Lucas isn't a good example of a beginner selling a big budget Sci-Fi
script. It's a fine example of a well known, Oscar nominated writer/director
struggling to sell a Sci-Fi script and succeeding.
Panos; what book should I read about Lucas to better know the story?
I read "Skywalking", "George Lucas: A Life" and even the very anti-Lucas
bio by John Baxter.