MMORPG are no different in this respect. The character is the defining trait of a Role Playing Game. The core of a game lies not in it’s virtual world, but in the character each player controls.
MMOs add complexity by having multiple players and a persistent virtual world, but the core of the game – to progress the story of your avatar – remains the same as it does in single player RPGs. This is true even in “sandbox” games where there is no defined progression path.
In some ways, character progression is the great weakness of MMORPGs. From a PvP standpoint, it lends itself to inequality. More advanced players are better by virtue of having played longer rather than having more ability or skill at playing the game.
From a PvE standpoint, what do you do once you have finished progressing the character as far as possible?
This problem is distinctly different than what we see in other games. For example, in chess or a sports game like Football, progress is isolated to just that game. Once any game is over, we reset the pieces and begin a new game. Persistent progress doesn’t exist, so there is no inequality and the "end" is welcomed and accepted as the finish until we start the next game.
The whole concept of the “end-game” is really just a way of describing what game gets played once you have reached a peak in character progression. The “end” in an MMORPG is a bad thing.
That’s one thing I always liked about Scenarios and Battlegrounds. They were some isolated games that have an “end” that could be played repetitively. In my mind, that’s not a horrible thing. It’s the implementation to make these games a grind through a reward system that cause problems.
In many ways, it’s too bad we need the reward to play these games. And I have come to the conclusion that we do NEED the reward. It’s become somehow tied to that character progression and without it, we’ve all been trained to think we’ve reached the end of our mousetrap.