Elephants are nomadic and they move from one location to another in order to find enough food, water and mating partners.
Apparently, If they stay at a single place, the entire vegetation of that place would be gone, It’s by nature’s design :).
They have a good memory and use a regular migratory path which covers hundreds of kilometers. If any encroachment in its path, invites enough disasters or conflicts.. and we complain about them!!