Good point. But he does make the notion that games usually have as good writing as the consumers who buy them, thus the stigma of being immature themselves.
That's kind of a self fulfilling prophecy, though. Also, games with bad writing will never go away, anymore than bad movies or bad books are going to disappear. The question is about games being made to appeal to a more diverse audience than just the minimum common denominator, which seems to be the focus of almost every game these days. Making the gaming equivalent of Old Man and the Sea should be a commercially viable option.
Fahrenheit, for example, was a game with "higher" goals than usual, but it still was only trying (and failing) to make the gaming equivalent of a good Hollywood blockbuster thriller.