It's difficult to explain. It just comes down the the individual. Some stories, scenarios and characters can really inspire, provoke and drive an individual to see more, some don't, and it sometimes doesn't have anything much to do with the story itself. Personal mood, current state of mind, even ones health.
A couple of things that may have contributed to my difficulty getting into the The Witcher is unfamiliarity with the lore as I hadn't read the books or played their previous games and the game seemed to overwhelm the the player with information in early going. There was so much think about and focus on at once it was more difficult to establish what the game was focusing in it terms of storytelling. I know that storytelling isn't as easy in an open world game, but I feel other RPG's like Skyrim and Horizon: Zero Dawn feed all the lore and active story elements in a way that was easier to digest.
Well, that's the best I can do to explain, I hope that's enough.