I decided to read Copplestone's History of Philosophy before popping up the next two articles.
One thing that struck me was the large number of independent schools that were concurrent with Socrates and Plato. Many were all run by the much maligned "sophists."
It was not until Aristotle started his own Lyceum that his work on scientific enquiry matured.
Legend tells us that the sophists had self-destructive philosophies ranging from relativism to outright hedonism. Of course, most of what we have was written in Plato's academy in refutation of the competition. This is a bit like basing one's opinion on private schools based on the disinformation pushed out by the teachers' union.
Another explanation for the many sophist schools is that they were started and run by [gasp] middle class Athenians who were trying to prepare their children for participation in the Athenian democracy.
Yes, such schools would teach students to argue from their perspective and would be geared to helping the little people with their little lives. Ideas that any self-respecting academic would hold in contempt.
There was clearly a major leap in the quality of the thinking between Socrates and Aristotle. I am thinking that this happened because, and not inspite of the diversity of schools.