I only had the 3 major networks' news for years. Depending on the location and schedule, they programmed for 5 and 5:30.
Many times at the end of one (5:00), I would switch to the other network (5:30). The one noticeable thing was the lack of variety. Both supposedly covered the World, yet their 30 minute broadcasts covered basically the same news items -- even on slow news days. Many of the reports on one network news were not only similar, but nearly word-for-word on the other network. About the only difference between one network and the other was the order of the stories covered.
I noticed the same.
For example, one day ABC would have a special "segment" on some rare ailment or disease, and the research on it -- and strangely enough, CBS would be covering the same topic.
I used to wonder -- who is controlling the presentation of the news?