[PeterisP]

The existence of the open internet made it beneficial to interoperate; lack of it would mean that the expected market interest would require them to not interoperate.

For many markets, the natural consequence of unregulated free market conditions is to aggregate towards a monopolistic or oligopolistic market, which isn't a free market any more. The idealized economic free market isn't a stable equilibrium - it's a good position for society, but it doesn't stay there on it's own, it needs to be kept free by preventing it from devolving into the monopolistic optimum.

[drawnwren]

What was the 'open internet'? I genuinely am not comprehending what drove AOL and Compuserve to tear their walls down.

[PeterisP]

While the internet as such existed, at the heyday of AOL&Compuserve residental users were not able to get a connection to internet as such at reasonable prices.

By the 'open internet' I mean the arrival of ISPs who offered consumers direct connectivity with all the internet, competing with AOL who offered connectivity to, well, AOL.

[em3rgent0rdr]

And what created the existence of the open internet? Voluntary interaction.

[intended]

Wrong - benign neglect.

The fact that the consumer was more nimble and capable of exploring and creating value in this space allowed them the chance to beat the entrenched players.

Today those entrenched players have finally turned around and are using their legacy power, connections and money, to make it an unfair playing field.