You may argue that they don't succeed by your criterion -- but those writers are reaching a much wider audience and having their experiments at writing and telling stories put to much greater test than just about any work of IF. As such, the industry has a wide user base to learn from and it's a user base that continually experiments with RPG, first-person shooter, and hybrid games, often moving between them, allowing a good interplay of idea and technique.
Do you really think there is a link between the size of your userbase and the amount of learning you can do as a writer? Yourself and two or three insightful critics -- wouldn't that be enough to learn what can be learned, and move on to the next attempt? I am certain that several thousand user reviews on Metacritic will not help, and my opinion of professional game journalism is not much higher. (Or maybe I am expressing that too negatively: many professional and non-professional game journalists do a good job reviewing games, but there is little worthwhile criticism going on.)
Also, as far as I can see most industry writers are (a) working on a team, and (b) not the creative director of the game they are making. This is surely a formula for failure, since ruthless solipsism is the hallmark of all good writing. Art is, I wouldn't say the expression
, but certainly the product
of a unique consciousness.