I don't think we're in disagreement. There is end-user value at least in short term. But when efforts are expended to keep users engaged with and thus financially supportive of closed systems instead of building alternatives isn't that folly?

None of the closed systems you mentioned exist in any meaningful form today and it's hard to imagine that a substantial number of Pidgin/Adium users began to sing the praises of XMPP rather than adopt another closed messaging system.