Education is a good. Like any good, demand for it stimulates supply.
In ancient Sumer, where writing was first invented, being a scribe was a high-paying and prestigious job. This was largely because
- demand for scribes was high, since their services (especially record-keeping) were of such benefit to the sate, and
- the engorged super-states of Sumer had tremendous purchasing power.
So in Sumer, a demand arose among parents for scribe-training services for their children. The first private schools in the world arose in Sumer (tuition-supported "tablet-houses") to meet this demand.
To be continued...