You have a good point there..

Every part of education was built

for a purpose, to serve an idea.

Primary gives kids the basic skills they need to begin to relate with the world we've built, sorta like learning our language .. The alphabet, the numbers we use .. etc ..and then they teach em how to manipulate these alphabets and numbers to do different things ..

this gives them the gateway into understanding the rest of our our world. All the stuff we're gonna teach em for the rest of education depends on this foundation (very crucial, doesn't meet disruption)