Can WebM already be called an open standard?

[J.B. Nicholson-Owens]

micu wrote:
> AFAIK, recently FFmpeg released a from-scratch WebM reimplementation,
> which lets criterion 5 (available in multiple complete implementations
> by competing vendors, or as a complete implementation equally available
> to all parties.) at least begin to hold.
>
> But what would you say: Can criterion 4 (managed and further developed
> independently of any single vendor in aw process open to the equal
> participation of competitors and third parties) already be identified to
> be true?

I think I don't understand what criterion 4 is meant to address nor do I 
see how an unencumbered from-scratch implementation would not qualify as 
satisfying criterion 4.

FFmpeg developers made a from-scratch free software implementation, so 
wouldn't that demonstrate anyone can "manage and further develop 
independently of" Google "in an open process equal to the participation 
of competitors and third parties"?  Didn't FFmpeg developers just do that?