My friend was also a bit skeptical about the cost, so I bought him a copy!
Seriously, I can say that no other game I have (except Rome: Total War, and that's only because of the mods Rome: Total Realism and Fourth Age: Total War) has kept me as involved and interested as Dom. It is worth every penny.
I also don't think it's just money. Some (most) people just don't want to spend the time/have the time to learn a game as complex as Dom.
That being said, I'd be more than willing to pay some more (though not full price) for a expansion pack/Gold edition that has an updated manual with all the new nations, and a complete bugfix.