There is a fourth reason to use a framework: onboarding.

It does not work much for Django, as every project I saw using it has a different shape, but it works very well for Rails, as all projects share the same structure. However, even for Django, there are some practices that a newcomer to a project should expect to find in the code, because it's Django. So, maybe onboarding on a LLM coded project is just picking the same LLM as all the other developers, making it read the code and learning what kind of prompts the other developers use.

By the way, does anybody mind to share first hand experiences of projects in which every developer is using agents? How do those agents cope with the code of the other agents?