Also kind of tired of Ridley being called the creator of the series. He's not really a sci-fi guy: O'Bannon, Cobb, Shusett all were. They knew Lovecraft. Scott invokes von Daniken. Moebius called him "an enlightened amateur". I think I agree wth that.
With a complicated, big budget film, there is no one creator in terms of the people involved. Big budget/complicated movies are a team effort.
Still, there is often going to be a debate about which person on the team was the most important in making a big budget/complex film which launches a franchise.
What does launch a franchise?
That can get confused with semantics and knowing the role of the director.
1. Follow the money; Movies that make good money can create a franchise.
"Alien" made money. That is why the studio approved the next sequel.
Why did it make money?
2. Scott as the director of "Alien", gets some credit for why "Alien" was a financial success.
- With a strong director, he / she is usually one of the main creative forces in a film.
When Ridley has a passion project, which is true of his science fiction movies expect for "The Martian", he is going to be involved with almost all aspects of the production.
3. Professional writers create stories but they may never get filmed such as with Asimov's "Foundation" series. Asimov being a professional writer has almost nothing to do if a movie franchise is created.
- Producers who get the funding and directors who call the shots on the set are usually not professional science fiction writers.
But directors who are not professional writers can have a tremendous effect in launching a science fiction film franchise.
- Take Star Trek movies. Director Robert Wise was not a professional science fiction writer but his "ST: The Motion Picture" made money.
The next ST movie, "Wrath of Khan", was directed by Nicholas Meyer who knew nothing about Star Trek so on that level would be an "amateur".
But Meyer was the right director. Of the thousands of decisions needed to make a film, Meyer made the right ones with "Wrath of Khan".
WOK not only made money but it started the formula for how Star Trek movies could be successful.
Leonard Nimoy has said that Meyer saved the Star Trek movie franchise.
4. Other directors who were considered for "Alien" before Ridley were going to make a schlock horror film where blood and guts were thrown at actors.
Scott as the director made many decisions about the visual look of the film.
- Importantly, Ridley guided Giger in creating the xenomorph and the Space Jockey.
- The movie's pace, use of lighting, the intensity of the film was mostly due to Scott.
* Once the team was beginning to form, no Ridley, no Alien franchise imo. In that sense Scott can be argued as the most important creator of the series.