There is a difference between marketability-testing, which is what Amazon Studios is looking at, and committee scripting which I believe is the way IRON SKY was assembled. Both are worthy experiments but the intent is different.
Of the two, Amazon's movie approach is more conservative; the creator is still in control of the shape of the product, it is still *their* project. With the IRON SKY approach, the "creator" is assembling the product from multiple contributor sources. It's more like the old Judy Garland-Mickey Rooney movies: "let's put on a show".
Amazon is just trying to avoid making an ISHTAR, a movie so out of touch with the outside world the producers--isolated in their Hollywood culture coccoon--never realized how bad it was, or ending up with a GREEN LANTERN or JOHN CARTER; quality movies that the studio didn't understand or know how to market to the proper audience. (I've run into a whole bunch of people who, upon renting GREEN LANTERN said "That was a great movie. I wonder why nobody went to see it?")
They are a small operation looking to leverage their resources to improve their odds of success because in today's "one-strike and you're out" movie market a weekend of bad weather can kill your movie. You can't quietly release a movie and wait for word of mouth to get out to its proper audience; you have to hype it to high heaven. And if the hype is the wrong kind of hype, you'll lose the proper audience and bring in one that can't appreciate your product.
It is the same problem, just magnified by several orders of magnitude, that most books face these days: finding an audience.