Most of the alternatives in use I can think come in genres where improvisation is far more important than playing exactly, and as such only a reduced feature se

Most of the alternatives in use I can think come in genres where improvisation is far more important than playing exactly, and as such only a reduced feature set is needed. Examples include the above mentioned tablature, solfege (https://en.wikipedia.org/wiki/Solf%C3%A8ge https://en.wikipedia.org/wiki/Solf%C3%A8ge), Roman numeral notation (https://en.wikipedia.org/wiki/Roman_numeral_analysis https://en.wikipedia.org/wiki/Roman_numeral_analysis), chord charts (https://en.wikipedia.org/wiki/Chord_chart https://en.wikipedia.org/wiki/Chord_chart), or lead sheets (https://en.wikipedia.org/wiki/Lead_sheet https://en.wikipedia.org/wiki/Lead_sheet). Full notation in the pop and jazz genres are rare. For Western classical, honestly, considering the information included in standard notation -- rhythmic complexity, phrasings, special symbols for various afflictions, etc. -- it would be really hard to replicate this in a system that's both easy for humans and computers to read. (Think if musicians had to use something like the piano roll found in most DAWs...)