Later, of course, but the agora began as a place for the surrounding farmers to sell their food to the town-dwellers. The same set-up has been used all over the world, for many centuries. I will grant you that the Greeks made good use of it for politics, but I'm sure other cultures had the same thing. The Romans copied the Forum from the Greek agora, but the Greeks probably copied it from somebody else.
on that you could argue the central location in a cave by the cave dwellers was an “agora”.
but as the article indicates and more than a few papers on the subject, the exchange of ideas is the major inovation. It was not just a place to dump out your veggies and sell them and discuss “ows da weather” in polite conversation.
It was the functional equivalent of their FreeRepublic with a store feature.