What's wrong about providing long-term motivation? I thought that was one of the positive aspect of a good game. MMOs are naturally long-term-orientated. They're good at that. What's supposed to be wrong about that? Of course I like collecting gear, mounts etc. It's fun. I like the continuity of it. I don't do it because I have some retarded feeling that I have to. And I wouldn't do it if the actual gameplay in WoW wasn't that much of a blast as it is.
You're not only labelling developers as ruthless manipulators, but also players as mindless sheep devoid of reason. You would do good to reconsider your overall paranoid mindset.