The openness of a system is entirely down to whether there is a single asymmetrically powerful participant.

An "open" ecosystem with a massive single player can change the behavior of the system at will.

The standard only has power if it has a long streak of being respected (making it more shameful to break precedent) or there's a rough balance of power in implementors.

That's why the definition of how open a system is not tied to the license of the IP or whether there's a standards body.

It's defined entirely by how hard it would be for the ecosystem to recover if the most important entity went evil, greedy, incompetent, or lazy.