I think it&#x27;s largely because the long-standing mathematical tradition comes from an era where those formulas always had plenty of context, be it that of a topic-specific class&#x2F;lecture or a paper that is published in a journal with a particular focus. Once you know what field of mathematics you&#x27;re dealing with, there are strong conventions for what variables mean what; that&#x27;s one of the things that has let to mathematics drawing from so many alphabets. It&#x27;s only been with relatively recent advances in information technology that the highly technical details of many specialties have been aggregated closely enough for the context to be lost.<p>Also, long variable names would greatly obscure the overall structure of many formulas, which could be an even bigger problem.