Because a media outlet that is trusted and good and has a significant following would keep people away from disinformers.
Unfortunately, we appear to have something towards the opposite - large media outlets that aren't good, aren't trusted, and are trying to manipulate the market (à la Youtube with it's now completely useless search and its nefarious recommendation algorithms) to stop people going to competitors who might actually be doing a better job.
Unfortunately, we appear to have something towards the opposite - large media outlets that aren't good, aren't trusted, and are trying to manipulate the market (à la Youtube with it's now completely useless search and its nefarious recommendation algorithms) to stop people going to competitors who might actually be doing a better job.