IIRC, the ancient Greek mathematics we learn about today was the university-equivalent mathematics of that era. Common people did not use geometric abstractions to figure out math problems. Before Fibonacci brought algebra to Europe, everyday calculations were done on an abacus. If no abacus was nearby, people emulated one by placing stones in lines on the ground.

Pre-university schools, even today, focus on teaching practical math. Most people can get by just fine without skills in abstract math, theorizing, and proofs (though those skill would make a lot of people much better at whatever they do).