It has been much longer than that. Duranty lied about the Stalin caused famine in the USSR and Murrow lied about McCarthy long before Kronkite lied about Vietnam.
I first learned long ago of the general incompetence and unreliability of news reporters. One of the first things that struck me was that in reports containing numbers there are almost always mathematical impossibilities, for instance, “The number of gizmowhatchits dropped from 99873 to 93789 in one year, a decline of more than twenty percent.” The math is almost always wrong. It has become even worse in recent years with expressions like “2500 percent less”, such expressions are used routinely now by people who are supposedly educated but can’t figure out that they are babbling nonsense. I figure that if they don’t understand simple arithmetic I can’t be expected to put much faith in anything else.