Perhaps it is also the case that many mathematicians are far to the autism side of the spectrum, and find it difficult to verbalize "soft" aspects such as motivation and intuition, even though those are extremely important in a textbook.
It's almost as if they partly lack theory of mind, and cannot imagine that somebody else does not know what they know, and consequently give explanations that are only suitable for someone who already knows the material.
It's almost as if they partly lack theory of mind, and cannot imagine that somebody else does not know what they know, and consequently give explanations that are only suitable for someone who already knows the material.