All of those comparisons to things that require quantifiable experience with the thing in question break down immediately, because how much excitement you can get from something can absolutely be judged from the outside looking in. I'm not going to go to see The Hobbit 2 because it looks an awful lot like 3 hours of boring stuff padded out from a book I didn't like in the first place, as an example.
If that's the kind of person you are, then yes. However, most of my excitement from movies comes from not knowing a damned thing about them - tis why I hate trailers. I can still enjoy them if I do know everything about them, of course - it's just not as pure. But that's an expectation thing.
The fact that you have experience with the subject matter in your example, by way of the book, actually invalidates your point on its own. At least for that example, where the book and movies are closely tied (if you assume that The Silmarillion is more of the same, in terms of your personal appreciation) and the nature of the typical narrative structure of books and films overlap, especially in such a "faithful" reproduction as The Hobbit movies.
There is plenty of scope for misconstruing, pre-judging and just missing the point altogether by "looking in" and not actually getting your hands on an
interactive form of entertainment (which movies and books generally aren't, although there is no real way to tell how someone's imagination would react to a book). If you "don't like" RPGs (as I
used to), then knowing a game is an RPG might be enough to "know" you "won't enjoy it", of course, but you won't actually
know without trying it (as I did once). That's why I think games really should be different, and why I hate the clamour for all the recent "sims" to be feature-identical (by way of comparison, in the sense of "X has it, why can't Y?").
Reviews are a different matter, since they're accounts of such experience, ideally framed within an explicit detail of the expectations, pre-judgements and any other kind of bias of the reviewer in question. Of course, reviews "spoil" the game as well as trailers spoil a movie, but I prefer so-called "emergent" games probably for their capability to restore that sense of unknown.
It's a giant grey area, I think.
As usual, I've come at this with no knowledge of how the discussion got here. I don't really know how it relates to sales figures, so apologies if I missed the point. That does mean I've seen it naïvely, and maybe with less bias than if I did know all of that. However, I did see "more excitement = better game", and recognise that "better" is meaningless; as is "excitement", to a degree.