When someone asks an AI for the best supplier in your category, there is no results page. There is one paragraph and two or three citations. Either you are in it or you are invisible.
The mechanics are not mysterious. Models lift short, self-contained, factual blocks. They rely on structured data to work out what an entity actually is. And they can only use what their crawlers are permitted to read.
Most sites fail at the third one by accident. A robots policy written years ago quietly blocks the crawlers that now decide whether you get recommended.