Are you saying that WebM, a file format introduced in 2010, is less bleeding-edge than H.264 MP4, a file format introduced in 2003? What definition of "bleeding-edge" are we using here?
Same story. Most browsers supported H.264 first (because it was dominant before WebM was even born). Internet Explorer, Safari and MobileSafari still do not support WebM. I don't see any reasonable way to say that WebM is well-established and H.264 is not.
