Comment by Aurornis
In my experience, the best case scenario for students (or anyone) who do these elaborate planning rituals is that it serves as a catharsis that moves their anxieties from their brain to some paper. Relieved, they loosen up and get back to making progress while forgetting about their detailed 5-year plan
The worst case is when this ritual produces a rigid set of unrealistic goals that the person almost immediately fails to achieve. This new sense of failure is compounded on top of existing anxieties and now they’re making even less progress than before while being even more sad about it.
Having supervised high-achieving students in undergrad research settings, I just tell them to chill out, be a whole person with friends and hobbies, and lots of things will just fall into place. The fact that they're where they are (i.e., fancy university, research group, yadda yadda) shows they're the kind of person to take initiative. The fact that they worry shows that they care. They're already way ahead.
The real gains at that point are in connections, reputation, and getting into the habit of physical exercise.