AI is definitely here to stay. You're right, a lot of AI may not have visible watermarks, but as you've said, the systems are definitely going to be putting in their code watermarks in the backend so that other systems can recognize that it's AI. I think there's honestly nothing wrong with integrating AI into a workflow, I just think people will need to be more creative about it to get the best results.
Big tech companies currently using it for security are just being too lazy and not integrating people to do delicate things as security because they just don't care.