However the duty remans, and it should be the primary--perhaps the only--objective of those controlling the media.
Whether or not they intend to rise to this duty, or want to rise to it, or laws require them to rise to it are all beside the point.
The duty of the free press to inform the public truthfully is as self-evident as the fact that governments derive their just powers from the consent of the governed.
I don't think either of those is self evident. The consent of the governed thing, for example, is interpreted by the government as "you voted, so you consent to the outcome."
And for the notion of "duty" are you just expressing a philosophical utopian vision, or a duty that exists in law?
Looking at the history of the press, it used to be openly advocacy material - half-truths if you will. The readers knew this. I think that's fair, it puts a burden on the reader.
Once you say the press is trying to achieve its duty to truth, you relieve the reader of the burden of skepticism, and even encourage people to trust what they read and hear, without evidence.
The press does an abysmal job of teaching and informing, and it will not cure this in my lifetime. Duty or not.