You're wrong.
And I shall now explain why
Context.
Roleplaying games are non-competetive games.
Their very genesis comes from cooperative play, a shift in paradigm from the wargames that gave them birth.
In a conventional RPG the Game Master is there to provide an interesting series of challenges and a good cooperative story. Not to wipe out the players. (Though some never understand this...).
What fun would it be to pit your first level adventurers against a great dragon right off the bat because the GM is in a vindictive mood?
None.
Roleplaying games, even your most basic dungeon crawl, rely on cooperation. The wizard to discern the magic, the fighter to hold the creatures at bay, the cleric to heal and the thief to open locks and disarm traps.
That, primitive, mode of D&D play is _still_ the basis for just about every MMORPG in existence.
Computer games come the other way. Computer games have often been adversarial or scorekeeping, you play to beat something, yet in one player computer games the trick is to make something challenging, not impossible. The game designer is out to intrigue, challenge and hook their audience, not to frustrate them (which these bloody race missions on San Andreas are doing to me at the moment
)
In Pong players are equal, they have the same size bat, its down to their reflexes and skill, nothing else. Their bat is just a bat, it has no history, no emotional investment in its existence.
Chess pieces don't have personalities and histories.
Risk, Chackers, card games, FPS shooters, everything you mention is NOT an RPG, not on the RPG model of play and, thusly, is entirely irrelevent.
That was always what was refreshing about RPGs, that you got together for a common goal, to have fun, you weren't competing to be the best. The only exceptions to this are, really, Paranoia and Vampire: The Masquerade/Requiem LARPs. In Paranoia the infighting is played for laughs, characters are disposable ciphers and dying is pretty much the point of the game.
Context.
In VTM/R LARPs there is a certain amount of satisfaction to be gained from backstabbing your rivals, getting them killed etc, but this can come down to political skill and innate charm as much as what's on your character sheet, keeping it half a step removed from the PvP in MMORPGs. However, it still causes massive problems. Players gang up to kill an NPC just fine with no arguments, player versus player? Then the arguments start about rules, justifications, lies, cheating, it never ends and it destroys everyone's fun.
You mention pitting your wits against a human opponent being more satisfying, I agree, but that's only really true in 'twitch' games like FPS. In an MMO its more like a trial of endurance, who has spent the most time levelling their character. Unless they're almost exactly on par in levels there is LITTLE to no unpredictability or skill in who wins. Even luck plays a very minor role.
Until we get an MMORPG that moves away from levels and hit point bloat as a mechanism of advancement that's always going to be the way. There's no involvement there, not even who can click attack the fastest.
PvP _IS_ the devil. It makes enemies of friends, spoils people's enjoyment, interrupts their fantasies and takes a large and unwelcome bowel movement in their fun.
How would you feel if you were playing, say, KOTOR and you approach the final scene to face Darth Whats-his-name when suddenly some ubered up dark jedi player runs past you, slaughters your entire party, calls you a 'n00b' and then sprints on chuckling madly. It would totally interrupt and spoil the play experience.
Everyone playing Ryzom is the hero of their own story and PvP knocks that for six.
I can see a limited place for PvP in resolving sections of the story arcs, so long as there can be clear winners and losers. Otherwise PvP is just a way for 1337 kiddies to get their kicks because they haven't discovered girls yet.
Trying to kill a much superior adversairy with 4 people and still beating the dust every time 
But that is war, somebody is alway's stronger and better organised or equiped and 1 must win) Sniping off wounded and stuck people was low and fun at the same time. *evil grin*
