Trying to kickstart expansion packs for an MMO would fail spectacularly.

That said, kickstarter isn't just for indie developers. It's also for projects that have a hard time getting backing from non-gamer investors and share holders. Projects that typically deal with mature content, or for retro-style games, or basically anything that isn't going to be mass-profit-shovelware-quality garbage like Call of Duty. Take a look at how well Project Eternity did, and that's a kickstarter by a top-notch AAA development firm.