>They were just regular dinosaurs, or started that way at least, but they were portrayed as much larger and much more resilient than simply a dinosaur revived from suspended animation would be.
Well sure, but that's basically the case for dinosaurs in cinema going back to the dawn of film. Few movies actually portrayed them particularly realistically. And even when they do, does that invalidate them? Gorosaurus is literally just the t-rex that King Kong rips the jaw off of. Does he not count? And if he does, then the T-rex from the original King Kong and the 2005 remake must count, right? But the original especially is clearly just intended to be a regular T-Rex. But it serves a very similar role to Kong (albeit a smaller role), and Kong is definitely a kaiju. And if the T-Rex counts, what about the other dinosaurs in the original King Kong? And then what about the dinosaurs in The Lost World? I think a big part of this is just how recent the discovery of dinosaurs, and gorillas for that matter, really is. When these movies were made, they were both recent discoveries, and not a lot was known about either, at least by the general public, hence why Cooper was so enthralled by a movie about a gorilla. They were new and they were cool. Real life gorillas are practically small kaiju. And real life dinosaurs are basically kaiju as well. Film dinosaurs, even if intended as realistic at the time, were portrayed as larger than life, because that's how people saw them, and still see them today. Couple that with how inaccurate our knowledge of them at the time was, and it makes film dinosaurs of the era seem even more monstrous compared to the real things.