Thats right! And FOX can make the most profit with just 1 film, if they release a film that could gross more than $500 million at the box-office. They don't need to release multiple films because that would require them to cash out more money. And you don't realize, if 1 X-Men spin-off movie completely bombed at the box-office or the heads of FOX became so disappointment with the box-office performance. It could jeopardize the movie series or harm the future X-Men movie releases. And just because they have the movie rights for over 100 characters, not all of them should be adapted into film. We are already lucky that we got 3 spin-off X-Men films - Origins, Wolverine, First Class. With the other studios, none of them released a spin-off movie. There's no spin-off for the Spider-Man characters, Hawkeye/Black Widow didn't get a solo movie after The Avengers, none of the supporting characters from the movie series Iron Man/Captain America/Thor got a solo movie. FOX was actually brave enough to release more than 1-spin-off movie. Most movie series didn't release a spin-off movie ever and if they did, most of them only released one and after that they continued releasing more films with the cast of the 1st movie.