I think the majority of parents wrote the talks for their younger children...and in many cases older children, too. I wrote most of my wife's discussions in the "demonstrations" in the school, too. Every time she was on stage, it was agonizing for her. She was, by nature, a shy and quiet individual. But one's standing in the congregation depended upon participation.
Years ago, the brothers who gave public talks had a wide latitude. Some of the most interesting talks I heard were by brothers who did their own research. Although they might have used an outline from the Society, their material was always fresh and interesting. However, in time, brothers were discouraged from using their own initiatives. "Outlines" practically became manuscripts even with time restrictions for every paragraph. The talks became boring and predictable. Obviously, it was another effort of the Watchtower Society toward conformity.
Does anyone recall some of the severe measures that were taken before the Ministry School because of the Watchtower dress code? In our congregation, some elders would examine the sisters to make sure their dress was proper for the stage. It was degrading and humiliating especially for those older sisters in the congregation.
One can only sigh a sigh of relief that we no longer have to put up with all this nonsense.