I imagine the kind of advertising you're talking about is obtained by providing that documentation and a curated training dataset to the providers.
Maybe even funding some training time.
The net result would be product placement, probably without having to declare an advert.
Kind of like when drug manufacturers provide subsidized workshops to clinicians.
I have a toy project that replaces a large part of our systems (disclosure: VR/AR @Meta), so that I can learn by doing, no intent to ship.
But because I have it thoroughly document and tested, and because it touches such a wide swath of adjacent real functionality..... my toy project is CONSTANTLY getting tagged as a dependency and assigning me reviewer on unrelated work. Because when my coworkers yolo Claude at a task, and Claude searches the codebase, it generally finds my crap very well documented. :)
This will go about as well as that did unless the models can be smart enough to identify when their training data is trying to coach them into being misleading at prompt time.
If I was Corp A competing with Corp B, what stops me, today, from flooding reddit etc with anti-Corp B material to pollute the model, and then paying OpenAI to not just nudge users towards me but also away from Corp B?
It will take some time to figure out the most effective methods and there will be some slow boiling of the frog so the users/products don't get too annoyed about it, but this is where things are inevitably heading.