hawkeyefan
Legend
I think where we are diverging @hawkeyefan is that I see the campaign, what the players and the DM actually play at the table, as the game. The RPG rules are there to facilitate and guide that game, but, they aren't actually what's being played. We play a campaign. We don't play the DMG or the Greyhawk boxed set. Those are just there to help us create our campaigns, which is what we actually play.
Now, in more indie style RPG's, sure, the creation of the campaign often gets spread around the table a bit more, and choices from the players might drive things a bit more than they might in more traditional games, but, the basic framework still exists. You don't play Dread - you play a game that is created using the Dread rules. You don't play Blades in the Dark, you play in a campaign that is created using the clocks of BitD. So on and so forth.
You can't sit down, open up the RPG's rules and just play. It doesn't work.
Sure you can. That's generally exactly what we do.
And even if it's not, the same could be said for baseball. You can't play without some basic understanding of the rules and processes.
The rules describe the process of play. The GM establishes a scene, and then asks players "what do you do?" We can call this the pitch. The players then take turns describing what their characters do. Let's call each of these a swing. Sometimes, a player may declare an action for his character whose outcome is uncertain. Let's call this a hit. The GM calls for a check, and then narrates a response based on the result. We can call this fielding.
There's a procedure that games follow and that's what the books layout. That's the same as the rules for baseball or any other game or sport.
Every RPG session (or near enough for this discussion, I'd say) consists of people taking turns and declaring actions for their character or characters, responding to the persistently established fiction that they're creating and sharing. The content that fiction will indeed be radically different from instance to instance.
The same way that a box score will be different from baseball game to baseball game. This is because the results of the established processes of play will differ for both.