Heh, did you actually read [MENTION=42582]pemerton[/MENTION]'s quote? I'll repeat it here:
At the end, you should have a situation not easily untangled and about to turn really bad. Some of the characters will be able to achieve their interests, concievably, but only by fighting and meaning it, and only by taking other characters’ best interests away. Dedicated rivals, aggressive enemies, and alliances fragile at best.
It’s time to start the game.
Oh, look at that, before you can start play, you have to create a scenario. Note, that whole "create" part. You can't play the game without creating the scenario.
I most certainly CAN play virtually any board game without creating a single thing. That's the point you're missing, [MENTION=23751]Maxperson[/MENTION]. Not that you can or cannot create material for a board game. Of course you can. But, you are never required to. You don't have to. You can play a board game, straight from the rules, start to finish.
You simply cannot do it in an RPG. Playing an RPG ALWAYS requires you to create the scenario. And that scenario is the game that you will be playing. It will be idiosyncratic to your table. But, at no point can you begin playing an RPG without first creating the scenario. It's impossible. Three examples now [MENTION=42582]pemerton[/MENTION]'s brought up and every single one agrees with my point - scenario creation must precede play.
You can play board games without creating a single thing.
Thus, RPG's are game creation engines. That's what separates them from other games. The fact that you MUST create the game that you're actually going to play before you play it. It might be days or weeks before, it might be a couple of minutes before, but, it ALWAYS comes first. Whether you want to call it shared fiction, or scenario or event or whatever, it doesn't matter. Whatever you want to call it, it MUST be created, mostly from scratch, before you can actually play an RPG.