gotk3 without generator

Why is gotk3 not created by a generator? There is e.g. https://gi.readthedocs.io/en/latest/ , why is this not used?

When projects start, it can happen from time to time, that the involved people don't have all the information. Because these people have never been in contact with this kind of work or just want to reinvent the wheel.

For example, these people want to learn the technique or have a small special case where the effort for a few manual bindings is manageable.

Then these projects grow and the effort to start at Zero increases, than just adding this one little feature. Oh and this is mostly done in the spare time of people between family and work.

Of course everybody is invited to help to create such a generator. Working together on a complete binding under one central location would be good for everyone.