They don’t have systems or habits for preserving knowledge reliably, and there’s enough competition between wizards that a lot of the best spells (not to mention methods for developing powerful spells) won’t be recorded, and might not even be taught.
They don’t have systems or habits for preserving knowledge reliably, and there’s enough competition between wizards that a lot of the best spells (not to mention methods for developing powerful spells) won’t be recorded, and might not even be taught.