I don’t think that’s the point it’s making, that the old person has a closed mind. Just that they seem to have ideas and values which seem e.g. morally ancient or something similar, but by the time you reach their age your values and world view will have changed to probably be very similar. I don’t see any values being placed on what they are thinking.

To me it’s not end of the story that’s the point of this, but the idea that when you are more social and engaged with different ideas your mind is more creative and energized and flexible. And there are other times, especially as you age, where you are more isolated and your mind slows and gets trained into rote thoughts. They may or may not be the same ones you started with, and they may be well earned and refined thoughts from a lifetime of experience, but stripped of the complex context they arose in, they are still just a simplistic starting point for the next round.