I am always amused when the journalistic world attempts to write an article explaining how to plan your employment career. It's a fool's venture. But such articles do need to be written. And they need to be scary so people stay awake and pay attention to what they must do next lest they become obsolete.
True. My pre-retirement employer kept reminding all of us that, although the company had done well and had a great future, we were responsible for our own employment. That meant staying up to date with the new technologies (which was almost impossible and required a considerable amount of your personal, unpaid time) while you were frequently using the old technologies day to day.
Although I managed to stay in the same general field my whole career I did have a myriad of responsibilities over that time, some of which I was better suited than others. Not unlike I have read about the radio/TV field on these boards. And although my last gig was over 21 years, there were many that lasted only a partial year or several years. Again, not unlike people here.
The days of working for one employer for an entire career are pretty much history but that can also make working more interesting and exciting. Nothing like the threat of losing your job to create a sense of urgency. (I am glad those days are over though.)