This has been a fascinating thread. And, thanks to
@Charlaquin for providing such an excellent and very patient defense of what I think is a very relevant element. I do agree with
@Charlaquin that RPG's are not games in and of themselves but are rather game engines. Now, before we do another round of arguments, let me provide a possible point that differentiates RPG's from games.
In every game, your initial starting point and moves are dictated by the rules. In chess, there are 20 possible moves for white to make, all of which are dictated by the game. Every chess game in history that uses the modern rules of chess is limited to those 20 moves. In Monopoly, there are 11 possible outcomes of the first move - you start on Go and roll your 2d6 and move that number of squares. In every Monopoly game in history, this is true. In basketball, you start with a jump ball and one side or the other will take possession of the ball and play will begin.
This also applies to video games as well. No matter how many times I play Baldur's Gate 3, I'm going to start on that Illithid ship with a worm in my brain. And my initial moves are constrained by the game itself. I cannot choose, for example, to jump off the ship.
((Yes, yes, sit down at the back, I KNOW there are variations of these games with different starting points, but, again, those variations will ALWAYS have the same starting point for that particular game.))
Now, what is the starting point of an RPG? What is the first "move" you can make? What are you options?
Well, there's no real answer to that. The rules in no way define a first action for the game. You can make a thousand characters and still not be able to actually play the game. Those first moves are defined by the adventure/situation that the DM (or sometimes the group, depending on the system) presents. So, if you're playing Horde of the Dragon Queen, you start in Greenest with a dragon attack happening. If you start in Keep on the Borderlands, you are at the gate of the Keep. If you start in my homebrew Spelljammer game, you find yourself aboard a Spelljamming ship in the middle of an attack by pirates!
The thing is, those initial moves are never defined by the RPG. They cannot be. Because an RPG isn't actually a game. It's a tool for creating games. You create your game (either as a DM, or potentially as a group exercise, again, it depends on the system) and THEN you start playing. The rules of an RPG in no way actually inform or constrain your initial moves which makes an RPG very distinctly different from games.