Maybe Nvidia did pay. All kinds of shady things happen in the business world.
If someone has 80% market of one product and you are a dev working on a game with that knowledge, you can't say that doesn't have some kind of effect. The nearest competitior is at 20%.
I'm using Nvidia and amd and not Intel cause iGPUs, while they make up all gpus as a whole most high end games don't factor them in as they will not run the game or will poorly run it ruining the experience. Intel dGPUs don't play a factor yet. In another year or 2, that could be a different story.
We seen stories where Nvidia drivers seemed to be favored/optimized over amd. Both have driver issues from time to time. Nvidia, seems more liked by most and has the least issues. Just how it looks. So, people will buy Nvidia. Numbers have shown that for the past decade or 2.