socially and politically powerful minority [e.a.]
It seems to me that the socially and politically powerful also have different needs and expectations of a language than the general population. They can put in the time and energy to use a complex and visually attractive script for ceremonial purposes simply because they have time and energy to spare as well as the ceremonies to organize. When the average Mary or Joe (Maria or Josephus?) becomes literate they want a stripped down functional script that is appropriate for grocery lists, contracts and instruction books. Preferrably one that is relatively quick to learn and "tolerent ov misstaks" A phonetic script would fit that better than a heiroglyphic one, wouldn't it?