I have long held the opinion that the demise of "real" news came about when news became big business.
Once the 24 hour news programs came into being, it required that people watch in order to get the ratings/money.
News as a business is as old as civilization itself. The newsreaders of Rome, who proclaimed the news of the day in the public forum, were well paid by whomever was feeding them the content ... be it Emperor, Senator, or Patrician.
Even since then, news has been a tool of The State or The Church (sometimes both) and could only exist with the blessing of those bodies.
William Randolph Hearst became one of the richest men in America publishing newspapers that told people precisely what he wanted them to hear (which was anything at all, true or not true that would cause them to buy more papers).
Until the advent of TV news and well after, every city had at least one paper that was representative of either the left or the right, and just as beholding to the politicians of those parties, and gave only those opinions. In many cases, papers in the same city represented opposing ideologies and competed with each other for the soul of the readers.
For a short time, network TV news was nothing more than a neglected add-on to regular TV broadcasting. Networks made little effort to strive for ratings because 30 minutes of national news at dinner time and 30 minutes of local news before The Tonight Show wasn't worth the pittance of ad money they generated.
When news networks became independent of TV networks and became their own cable entertainment channels, they knew they couldn't get sensational rating with the middle-of-the-road pablum of network news ... they needed a return to the sensationalism that newspapers have relied on for centuries to secure a loyal ideological base.
Unbiased news isn't a new thing. There have been very few times in human history when news wasn't biased.
However, our naive expectation that news
should be unbiased is a new thing. We cannot afford to be this naive in our modern era.