Comment by SergeAx

Answering a headline question: Dinosaurs are not patentable. You simply can't make T-Rex part of the studio's IP portfolio. Spielberg's franchise is based on the park's identity, including its font, logotype, merchandise, and more. I am 90% sure he had real theme park(s?) in mind when developing the first movie. The movie industry has long envied Disney's parks, which provide a steady income stream, regardless of whether new movies are produced or not.