Asked on Twitter what would have happened if Fox never owned the rights to the X-Men and Fantastic Four, Gunn stated that Guardians of the Galaxy likely would have never been made.
It’s a hard question. Kevin Feige was into the idea of Guardians because of his deep love of Star Wars and space operas. But the Marvel Studios schedule might have been too glutted with content/movies and it would have never been made. https://t.co/UHeQLbT7Zy— James Gunn (@JamesGunn) January 11, 2018
His logic follows that if Marvel had the rights to the X-Men and Fantastic Four, the production schedule would have been far too glutted for GotG to even get a chance. Since those two franchises are far bigger and more valuable than Guardians, Marvel would have focused on them first.
As Gunn puts it, Guardians of the Galaxy was made because Kevin Feige loved Star Wars and space operas, but there would have been no time for that if X-Men and Fantastic Four films were also being planned.
Now that Disney has acquired the rights to the characters again, Marvel Studios gets the best of both worlds. It gets two popular franchises, and in the meantime, turned the Guardians of the Galaxy into a success story.
Between the two films, Guardians has made over $1.5 billion in worldwide box office returns, with plans for a third film for release in 2020. It's all seemingly worked out for the best.