These days, you can't start with the assumption that a story is written to J standards. Rather, you need to start with the assumption that it's pushing narrative, and hope to be surprised.
More personally, I took a J class during this period and wrote for a school newspaper. The instructor talked about J standards the way NRA instructors talk about gun safety--it was practically a religion.
These days, if you want facts, you have to plumb the cesspools of the right and the left and work it out for yourself.
Not saying that this problem never existed in the past, but it is far far worse now.
Go watch Walter Cronkite's reporting on the Kennedy assassination. He and his news room is just reporting the facts as they get them with no editorialization or agenda.
I could be wrong but I think the far bigger difference from then to today is not the quality of the journalism out of mainstream outlets but that the plethora of outlets available has removed the necessity of consensus myth making. Instead of a collected national myth that Americans share they can now choose their own myth.
They used to have to bend their views somewhat towards the major news because people seek to resolve their cognitive dissonance. Now they can change the channel. As an example, my parents are conservative and when Walter Cronkite criticized the Vietnam War and journalists put direct images of the conflict on TV they praised that. Yet when mainstream news which had generally backed the war in Iraq began to report on things going wrong there my parents were livid. When news outlets began reporting on soldiers dying and reading the names of the dead they were even angrier. Nevermind that the news was unable to air the kinds of direct footage of war they had in the 60s because the military had become much savier about the kinds of situations they let reporters into.
I think major news had almost the exact same, pro establishment, upper middle class ivy league bias it has today. I just think it's easier to confirm a contrary opinion. If Fox News existed in the sixties I think it would've run with slander stories about MLK for example and might've hampered Civil Rights. But they didn't exist and general regard for MLK as a hero became the default myth.
Again, I could be wrong but I think it's a perspective worth putting up against the common narrative.
There's not a specific moment in time. There are specific innovations that accelerated and commodified the dissemination of facts, which each contributing to this decline in journalistic integrity and greater faithfulness to facts.
So is your gripe generally applies to all contemporary journalism or specifically with CNN and Fox News? Isn't it just as likely that legacy news sources are still doing the news pretty much the way they always have but that the availability of alternative sources has allowed people to diverge their opinion from a mainstream one more than they could before? (Which I'm not saying is good or bad. I think it likely has benefits and drawbacks.)
Case in point: The Economist. Certainly one of the historically and currently most respected publications.
The Econsomist never claimed not to be biased. In fact they proudly produce opinion journalism.
The point, however, is that their reporting is fair and considers the other side of the argument and that the're absolutely open about where they stand.
Foreign Policy is another good example coming to mind.
News is produced by humans and humans have biases and always will have.
What's new is massive lying on an industrial scale and the fact that facts seem very relative nowadays, depending on the news medium.
I think in some respects we're better off now. An outlet like The Intercept couldn't exist 40 years ago. They have a clear bias but some of the stories they break are huge and are exactly the kind of thing the NYT in its heyday would've sat on.
Our old media system had the benefit that it helped create a fairly singular truth for people to follow. But it created what I think was equal to the massive lying you are concerned about by just not reporting on lots of stuff.
https://www.theatlantic.com/politics/archive/2013/06/why-doe...
I definitely agree that having a much larger ecosystem of news outlets is a big plus of the current era. One can almost watch the flow as things get leaked/scooped on obscure sites, and then often end up after a period of days/weeks/months on one of the "real" sites. (The Damore story and internal Google message traffic is an example.)
The downside is that it's a real grab bag of good stuff, junk, agitprop, and so on. In effect, we've all become journalists, in charge of sifting and verifying information to assemble a NPV story.
And it seems to have become acceptable (on both left and right) for a news room to try to "get" a sitting President that they don't like, even if the result is sloppy journalism.
My impressions is that serious retractions (or worse, serious errors without retractions) are far more common now than thirty years ago.
As for MLK, even knowing what we do now, I still consider him a hero. But yeah, journalistic coverage of him back then was pretty uncritical.