Yes because normal people would take something like Pokemon that seriously! Most gamers don't, because it's just Pokemon. I enjoy it for the simplicity of it but how fun it can still be to play.
Yes pretty much every MMO's community sucks ass, but I just think that if a Pokemon MMO was made the community would be as bad as Runescapes.
And then if Nintendo made it they'd censor it so much it wouldn't really be an MMO. Put into the right hands, this could be a great game, but I still don't think it could be done.