Kids have always love dinosaurs but making movies starring dinosaurs was difficult
So if you wanna cash in on that love you just throw some faux leopard skins on some folks and shoot 80 minutes worth of cavemen footage followed by 5 minutes of rubber dinosaur fights and bam, you have a movie that leaves a huge imprint on every pre-pubescent who sees it. Years later those people grow up and make a lot of media starring ugly cavemen so they too can cash in on kids who love dinosaurs.
Then Jurassic Park happens and you no longer need the caveman angle cuz DNA is real, and most people believe in it. You don’t need cavemen, or time travel, or hollow earth. You can just say “we cloned some dinosaurs” and then kill a ton of them in the modern day, or at some point in the future. Turns out no one ever liked cavemen. They were just an excuse to go on dino adventures. The end.