It is very possible. Sol Max created a 17k line monolithic file in a prototype not long ago. If I didn't stop it and make it refactor everything it easily would have went to 60k. I think it's the default if you start a new project and don't define the architecture concretely with files and folders beforehand. Models have zero concept of architecture or long-term planning, they just band-aid the fastest immediate solution that gets them the reward.

I find that specifically when you tell it you’re doing a prototype or POC, it takes that as a license to write huge single files and other shit coding practices.