I think it's something different in A Game of Thrones, and it was a deliberate decision of the author. I imagine him going "you see, this opens like the typical fantasy novel, there's some dudes who are likely the heroes or related to them, and there's some monster, and this novel is going to be about them"... and then BAM! -- all those tropes are subverted. The novel is largely about something else, and these were not only not the heroes, but they weren't even important characters!