Aye, The Hobbit is a no brainer. The problem is, it's *such* a no brainer to make gobs of money that the contracts and licensing fees to bring the disparate rights holders (MCA and New Line/Warner), director/writer/effects/props and actors together in order to do the Hobbit whilst Ian McKellan is still fit enough to do the role of Gandalf is a narrowing window of opportunity.
When LotR was a big risk, the price was relatively cheap. There is no perception of risk now if Peter Jackson directs, Fran Walsh writes and Ian McKellan stars. And so the price from everybody involved has escalated dramatically.
It doesn't help that Jackson is fighting with New Line over accounting anomolies and self-dealing that screwed him out of 100 million USD either. *sigh*