I think he's almost saying something else. He's suggesting that sandbox narrative is the best thing for games. Whilst I don't wholly disagree--some of the best parts of games like Silent Hunter 3 are the action reports some people generate afterwards--and whilst I don't want to compare the different mediums directly, it's a bit like suggesting kids playing Teenage Mutant Hero Turtles in the playground is better than watching the show. In some degrees, it is, in others, it completely isn't.|
Plus there's the other issue that making gameplay narrative all about emergent sandbox gameplay could make for incredibly lazy storytelling--"we don't need to come up with a solid setting or story, we'll just let the player fill in the gaps". It's almost along the same lines as representational graphics vs realistic ones--make graphics sparse and purely functional, even just something like ascii, and the player's imagination has to fill in the blanks and thus becomes better than if we detailed it intricately with phong shaders etc etc--again it's not a theory I necessarily disagree with (look at Dwarf Fortress), but it's not a one-size-fits-all thing and could again simply be used as an excuse for creative laziness.
Interactivity is the thing that separates games from other mediums, true, but that doesn't necessitate giving the narrative power to the player in themselves. Look at A Mind Forever Voyaging, Walking Dead, and to a lesser extent Braid or Pathologic. They're all flawed in their own way (especially Pathologic's dodgy translation issues), but they all have narrative that could only really be done in games, yet all ultimately have completely linear stories and no real emergent gameplay to speak of.