Like a tree
Like a tree, people who have lived a long time in a certain place, have made very long and difficult roots to start. If for some reason life wants to offer them another place to live, it will be almost impossible to move them, their roots are so attached to that soil. Cutting the trunk is not the idea, but it is the sensation that they have to feel when they abruptly leave the ground that nourishes them to take root in another.
It is a somewhat complicated situation, but it really is an analogy. We are human beings that by nature, we should be a nomadic species, according to the environmental conditions established in a certain place, without limits. On the other hand, the Earth also offers us innumerable places to live, where to make crops, where to make a balanced distribution of society and the supplies it requires for sustenance and life.
But this happens in a perfect world, we are perfectible, but we have not reached perfection in that aspect. Today there are large masses of people fleeing their roots to get new ones in other latitudes, those who suffer these exoduses are the elderly, in most cases. I remember a phrase that says something like: we do not run away from a place, we run away from people. And it is the thing in most cases, it makes us leave the ground rooted.