Not really. There's typically a main antagonist in most games, so in that respect yes, but there are tons of non-RPGs that don't involve saving the world and deal in smaller conflicts. I think that's the main issue is that it always has to be ridiculously large scale in an RPG, and the world and or universe is always in immenent danger and you must save it personally. I'll stick with popular to semi-popular games here that don't involve saving the world either at all or directly. Resident Evil, Grand Theft Auto, Gears of War, Resistance: Fall of Man, Hitman, Condemned: Criminal Origins, Dead Rising, Tomb Raider, Batman: Arkham Asylum, Assassin's Creed, Uncharted, Left 4 Dead, Saints Row, and many, many more. There's a laundry list of games that deal in small scale conflicts that either don't end in you saving the world if there is a world saving conflict going on, or the world simply isn't in any danger at all regardless of the outcome of the game.

Not really. There's typically a main antagonist in most games, so in that respect yes, but there are tons of non-RPGs that don't involve saving the world and deal in smaller conflicts. I think that's the main issue is that it always has to be ridiculously large scale in an RPG, and the world and or universe is always in immenent danger and you must save it personally. I'll stick with popular to semi-popular games here that don't involve saving the world either at all or directly. Resident Evil, Grand Theft Auto, Gears of War, Resistance: Fall of Man, Hitman, Condemned: Criminal Origins, Dead Rising, Tomb Raider, Batman: Arkham Asylum, Assassin's Creed, Uncharted, Left 4 Dead, Saints Row, and many, many more. There's a laundry list of games that deal in small scale conflicts that either don't end in you saving the world if there is a world saving conflict going on, or the world simply isn't in any danger at all regardless of the outcome of the game.

I wouldn't argue that the world itself is in danger in Gears of War, but you're still fighting for humanity (and pretty much 90% of the important things are done solely by Delta Squad). I don't know if that one is such a good example. 

The difference is that in Gears, you're stopping what would be a Lieutenant of the bad guys, not the leader. You're nothing more than a stop-gap in the first two games. You thwart the enemy but don't actually stop the "big bad guy" from destroying the world.

On the other hand, in many JRPGs, you bascially play a role where a teenager rises to power and kills Hitler. It's really stupid when you think about it.

Marcus Fenix, bad-ass soldier. Goes on mission, kills minor leader of opposition that stops enemy invasion.

Final Fantasy, random teenager with ridiculous ties to maniacal power-hungry madman gains power and destroys enemy, saves world.

Which one sounds more logical?