Well, yes of course, it takes more than one person to make a movie.
But Ian's and Elijah's and Viggo's and Liv's acting (???) do not determine the overall success or failure LOTR
It is the Director who says "Action" and the Director who says "It's a wrap" (or words to that effect).
That is, nothing happens without the Director's leave.
He
directs pacing, lighting, camera angles, actor placement, even actors' delivery of lines, if not the dialogue itself.
LOTR was produced by [companies] "New Line Cinema assisted by Wingnut Films" [per Wikipedia].
Wingnut Films (a NZ production company) is owned by Peter Jackson.
New Line put up most of the money (note the "
assisted by Wingnut films").
It is the Studio that makes or loses money on a film, not the director (unless, as with PJ, the Director also happens to be putting up production capital).
If a movie dies at the Box office, the director still gets his contracted salary. But he may have trouble finding future work as a director, because studios may be leery of his competence.
It's not a case of picking someone to get the credit/blame (for appearance sake) or saying "the entire team is responsible for losing the game".
If the owners of New Line were unhappy with the any part of the making of the movie they fire PJ---not PJ AND Chris Lee, AND the guy making the big-atures AND Liv Tyler. (Oh, wait, firing Liv Tyler would have been a good idea from the get-go).
They might also fire the screen writers.
(Back in
the Golden Age of Hollywood Studios had much more power over filmmaking, including the minutiae. )
So perhaps we should agree to disagree on this.