Perhaps we should take a closer look at what actual happens at the table when we play RPGs. Humans are, by nature and context, story tellers and forgers of narrative, and that I think, perhaps more than something more crafted, constructed, and specific like plot is what's at work. Imagine if you will a dimly lit basement, smelling faintly of cheetos and mountain dew..
The basic unit of RPG play is what I'm going call the situation (as opposed to scene, which has more baggage than I'd like, descriptive as it is). So the situation begins with the GM who provides the players with the necessary information to explain the current state of affairs, mostly in the form of evocative description. This might be bolstered by the players asking question to clarify or expand on the information. Then the players have to decide what to do - they must act. But how do they decide?
Obviously, a big part of that decision is framed by the GMs description and clarification, but that's only a part. Another part of player decision making is informed by their understanding of the setting and genre of the game, and this part is based on experience. In addition to setting and genre, the players might also act based on context clues within the GMs description - for example what the GMs spends time detailing vs the other, fuzzier and less well realized elements. In addition to all this up front stuff is that very human story telling drive - they fill in bits here or there, make unstated connections and inferences, and generally weld the bits together. These merged elements form the basis of their understanding of the situation and their decision is based on this new understanding. But they don't actually act, they state their intention to act, a desire to change the situation in one or more ways.
The situation now passes back to the GM who takes both his initial description, and the actions description of the player, and feeds it through the heuristic of the rules (to decide about die rolls etc). The GM then describes a new state of affairs that include the player actions and the consequences of those actions. Newly reframed, the situation is handed to a new player and we begin again.
Some of these bits sound like storytelling, but other really don't, which is why the storytelling descriptor only gets us so far. There is, I think, a lot interpretation happening at each step which makes me think me that it really deserves its own words and description. I also think this ongoing exchange of interpretation is a big part of what makes RPGs such compelling fun.