Essentially the theme (excuse) of the game is "you should have already suffered the consequences of your issue, but for some reason you haven't.. yet."

The game does a good job somewhat pushing you towards finding the cure, but makes it clear that it is not something that is easily cured. A healer might tell you it's above their abilities, another NPC might tell you they can handle it but are missing advanced equipment to do so, and so on.

It does that balance well that you wouldn't care how long it takes you to do the main objective, but reminds you that you need to do it at some point.