Stargate SG-1 was born from the Stargate movie released in 1994—but the film's original creators had nothing to do with the making of the series. The popular show went on to have 10 successful seasons and inspired several spinoff series and films. All this started with the original movie created by Roland Emmerich and Dean Devlin, which everyone expected to fail. Ultimately, this significant underestimation led to MGM taking ownership of Stargate, and though this meant the creation of Stargate SG-1, Emmerich and Devlin were blocked from participating in the project.

https://screenrant.com/why-stargate-sg1-roland-emmerich-creators-not-involved/