doesn’t Disney own them all? even universal pays them royalties.
Disney owns Marvel the publishing company and Marvel Studio the movie company. Marvel Studio started owning them all, but Marvel was in very bad financial shape as a whole so they licensed out stuff to get money. Luckily they licensed wisely, made a lot of money from the movies and increased readership, and got to see how to make a good superhero movie. So while Marvel owns the characters they don’t own the movie rights to many of them, though they are in the process of getting them back as much as they can.