PBS did a special on how TV news came to dominance with coverage of the JFK assassination called "JFK: Breaking the News".

https://www.pbs.org/video/jfk-breaking-the-news-d7borr/

Similarly, CNN essentially became the mainstay with live coverage of the start of Desert Storm in '91.

https://en.wikipedia.org/wiki/Media_coverage_of_the_Gulf_War