This is a very valid question.
If we go back to late '60s and Vietnam war - what did we have then? What have we had with the image of the Vietnam Vet?
It is demonstrable that the "News" has been slanted for at least that long. This is demonstrablebecause real people are still with us who know what really happened, and data is a bit stronger on more issues since the '60's than before.
Note that at the end of the Anita Hill perjury >60% of Americans believed Clarence Thomas. One year later >60% believed Anita Hill. The only external input was media representation of the case.
I agree with others posting - it is less intentionally fabricated stories, and more the filtering and biased reporting of stories (intentional or not) that are the majority of the problem. I think the fabrications are just evidence of the extent of the slide, from leanings, to unintentional bias, to journalistic activism, to intentional bias, finally ending in pure fabrication.
Note that this is also happening in environmental science, and within the sceince of endangered species (I can't remember the exact case a few years back where the scientists were taking some sort of fox haris of an endangered fox and planting them in new areas, so that these areas could be claimed as fox habitat).
My personal theory is that many of these things can be traced to the reduction in value placed on honor in our society.
Diva's Husband
"it is less intentionally fabricated stories..."
The worst kind of 'fabricated story' is, perhaps, when the media manufactures events so that they have a 'better' story.
Case in point - mid '79 to mid '81 I lived in Northern Ireland. I was there during the hunger strikes in H-block in the Maze. I was there when Bobby Sands finally succeeded in committing suicide by not eating. There were riots in Belfast. There were British police/soldiers out with their armored personnel carriers. Activity was too slow for some American TV crews. They paid boys on the street to throw Molitov cocktails at the APC's. Manufactured news event. Raised the ante in the 'riots' to 'newsworthy' level. Having witnessed that sort of thing, I have often wondered how much else of reported news events have been rigged to make them a story.
You also make a good point about the reporting during the Vietnam war - MSM, Hanoi Jane and Hanoi John caused the loss of that war. Before Jane and John (F'n Kerry) got into the act the North Vietnamese were considering surrender.