They get to screw Apple. Apple has built an existing HW ecosystem and has a highly tuned sw tools for H264. With WebM Google gets to say, "Throw all that away -- now you're behind us technologically Apple."

Regarding Apple's "highly tuned sw tools for H264", you know that their H.264 encoder in Quicktime/iTunes is abysmal, right?

There's an x264 plugin for Quicktime which is much preferable to the encoders built into most proprietary products, but Apple's is particularly bad.

And Apple is telling Google GFY and taking record profits. Why is that state of affairs going to change?