Asking this question is a good place to start, but the answer goes way beyond mere reluctance. I would say that many people are very intelligent in ways that ou

Asking this question is a good place to start, but the answer goes way beyond mere reluctance. I would say that many people are very intelligent in ways that outstrip their ability to communicate this knowledge effectively. Natural written languages are very blunt instruments in contrast to the highly-involved abstract concepts that our brains are capable of 'discovering'. Some things are very difficult to explain effectively and take much patience, forethought, style, and lengthy prose. Fewer are talented in this area, or you might say that certain skill sets intersect less frequently. (Talented writers and talented mathmeticians/scientists). Even great professors often struggle with explaining things in layman's terms. Take the English laguage, for example. Very flexible, but still feeble at tranferring highly abstract concepts. It wasn't designed/evolved for this purpose, so this is not surprising. Talented writers can get quite far on the abstraction scale, before text becomes a verbose and confusing mess, but there must exist a potential space for a future spoken/written language to be created, better suited for explaining abstractions, somewhere between the current common natural languages and terse mathematical notation (which itself requires much textual explanation).