It appears you are looking at it from the wrong end of the information chain. The reason youngsters need to be so expansive in discussion is that they are still in a learning proccess. They need to explain the concepts they are trying to express. As one gets older and has an older audience it becomes a given that most of the core information is understood by their peers and the long explanations are not needed. I presume that when I turn 90 a simple grunt should cover almost any topic.I found it bizarre that the 20-somethings and 30-somethings seemed to be carrying on a conversation, while the 40-somethings seemed to be throwing out random comments that had little or nothing to do with one another.
On the other hand when the older talks to the younger, a longer explanation should be used to compensate for the lack of experience and accumulated knowledge. When the shortcut is taken with a young person, the meaning is lost since there is no reserve of information on which to draw.
Thus the younger the listener, the longer the conversation... such as with the length of this message compared to the one sentence that could otherwise cover the entire matter.