Perhaps a person's psyche will change, given the change in perspective a longer life could induce. After all, a child has many erroneous perspectives, and yet is able to adapt. With longer, healthier lives may come the freedom to re-examine old ideas. I hesitate to make sweeping statements, however, since this is psychology.

What I can say is that it is fallacy to assume one can extrapolate into the unknown by projecting linearly, or even statically, the known. In this case, why should the old be locked into old views? Wisdom urges always incorporating the latest information. People persist in wrong thinking after being shown right - this ego grasping may be a symptom of short lives, for some. And yet, certainly the desire to live longer is, at (the very) least in part, ego grasping, but that does not mean a sentience with infinite longevity will engage in ego grasping forever. Forever is a long time. -Eventually even the most ego wrapped ``child'' should grow out of it, if he or she grows at all.

New challenges give us the possibility of change and new ideas. Certainly re-doing life's challenges again with new minds does induce humanity to take on new ideas, as you say. Maybe there is something of the breadth first vs depth first search style in this comparison. Surely both can have their place.

What is presented without evidence can be dismissed without evidence. But this statement can be dismissed twice: Not only is it not established that brevity gives life meaning, it isn’t established that life even has or needs meaning!