But that means the essential elements of D&D and RPGs in general may not, in fact, be essential at all. The open-ended, long-term aspect of playing a character from zero to hero? Just a side effect of maintaining continuity; the character has to change, so you need a way to track participation (XP) and a way to express the effects of change over time (Level.) Roleplaying itself, including immersion? Another side effect: alliances, grudges, side quests, shopping expeditions, and everything else is just "continuity" that happens between encounters or challenges. The entire fictional world, and all the rules for determining what happens in it? Side effect. Any of these may be enjoyable, may in fact be the main thing you enjoy, but they're just side effects. Roleplaying is really just a way of playing multiple games as if they were part of a larger whole.
The conclusion I draw from this is that the traditional explanations of what roleplaying is -- what we say to the non-roleplayer who asks what we're doing -- are all completely wrong. You usually hear: "it's like cowboys and indians, but with rules to prevent arguments about who got shot." Or some other variation of "it's let's pretend, with dice". Or you hear the explanation that it's about creating a story, or it's like a computer FPS or MMPORPG, but anything can happen. That last one is close, but it makes two errors: it focuses on the fantasy and the fighting, which are only accidents of the historical development of RPGs; and it mistakes the open-endedness as a goal of RPGs, when it's actually a means to achieve the goal, which is just continuity.
Imagine instead that RPGs had developed out of Monopoly. People sometimes use Monopoly in discussions about RPGs, anyways, so it doesn't sound so far-fetched. But now, knowing that the key element is maintaining continuity, it's easier to figure out what the parallel universe RPG that grew out of Monopoly would need.
- A character sheet, which preserves a monopolist's current properties and cash on hand from session to session. You might also want extra scores representing Fame, Respect, Trust, or other abstract qualities.
- A way to handle new players entering in the middle of a multi-session game, or players leaving. How do you handle the properties of a player who isn't present? Do you allow hostile takeovers of railroads or hotels when the player can't defend?
- A way to handle board expansion, maybe just a second Monopoly board with the understanding that it represents multiple "other cities". When you land on a railroad, on your next turn, you can jump to the same railroad on the other board and name a new city; you can't come back to the main board until you land on the same railroad. Use the property information of the squares on the other board, but each property must be renamed by the player that lands on it. One player keeps a record of cities, which railroad connects them, and the properties unique to that city.
- A way to handle improvised actions. Let players skip a turn to declare any other action, such as "I hire thugs to burn down the hotel on Park Place" or "I run for mayor" or "I seduce the warden at the prison." Everyone decides what's an acceptable benefit, as well as a potential backfire effect; seducing the warden, for example, might be the equivalent of a get out of jail free card. Roll 2d6, 9+ succeeds, snake eyes backfires.
As people played this modified version of Monopoly, they'd come up with more additions, most being modifications of these or the official rules. For example, the rules for adding a city could be turned into rules for government interaction, with each property representing a government department or official, and the money spent on them is fines or fees or other standard costs. The hotel and house rules would be replaced with bribery rules, which would have a chance for being caught and imprisoned.
And as people expanded and spread the idea of Long-Term Monopoly, they would begin to focus on the side effects. Some people would play very "Dynasty/Dallas"-esque versions, with lots of parties and social interaction between the players. Others would focus on emulating specific stories of greed and corruption, adapting the auction rules to cover introduction of dramatic story elements. Others would focus on real-world simulation, adding rules to make prices more realistic or adding steps in the process for purchasing properties. And each faction would begin to think of their particular interest as the real definition of an RPG, and there'd be lots of terrific fights online.