Sure, you could have an "open standard," but someone is controlling that, too.
No, that is why it is an open standard. Once it is out there, anyone can implement it and conform to the standard. Maybe someone maintains it and maybe someone is working on the next version, but no one controls it. To illustrate the difference, what platforms does DirectX run on? Microsoft Windows, Microsoft Xbox, and Microsoft Windows Mobile. Notice the pattern? And what platforms does OpenGL run on? All of those plus dozens or even hundreds more. If you want to port your app to the iPhone or the Palm Pre or an Android phone, who is going to have to do more work, the person with the app programmed in DirectX or the person with the app programmed in OpenGL? That is the advantage of an open standard.