Why didn't it happen? Warner Brothers began developing an adaptation in 1995, and shooting was scheduled to begin in 1997 with Scott behind the camera and Arnold Schwarzenegger starring. However, growing concerns about the $100 million-plus budget and the bankability of the star, the director and the dark, artsy, psychological script with minimal dialogue (that was later rewritten) led the studio to pull the plug.
Will it ever happen? Seeing as the project was eventually made in 2007 with Will Smith starring and Francis Lawrence directing (earning over half a billion dollars worldwide), there's virtually no way Scott -- or any other director -- will tread that same ground in the foreseeable future.