I feel you on this. I think most people sort of suspected TGA to be more heavily biased or influenced only to games introduced by large companies. These few latest ones though I think opened the eyes to many, especially with seeing how many game journalists are bought out. There is a fine line between focusing purely on graphics and expanding on ways to tell stories and I think both should be recognized appropriately.
But yes, most of it is similar to Emmy/Grammy/Whatever type of award. They'll throw in some smaller titles here and there, but it's primarily who is already dominant in the industry and who can manage to throw around the most money.