Unlike with numbers, day to day language needs to convey a larger variety of concepts hence why logograms are still needed. Much like how more advanced math requires different symbols and operators that are akin to mathematical logograms to convey additional concepts beyond the fundamental quantities of 0 to 9.

Alphabets are often linked to sound, and it would be a tremendous challenge to create an "alphabet" analogue that links to a set of fundamental concepts that you can somehow rearrange to form higher level concepts and can still be universally understood without it linking to sound.