Modding has been a part of gaming (legal or otherwise) almost since the medium has existed, and considering Bethesda has released a creation kit alongside their game, they'd prefer to keep their players modding in the legal sense. While it's almost impossible to fully complete this fifth instalment fully simply due to how vast the game is, once the main questline is finished and you've put your allegiances to your chosen factions, the game can feel a bit samey after a while. A phenomenon beyond any expectations Bethesda must have had, it's been ported onto every console imaginable and kept well and truly alive on the PC through a dedicated modding community.