There are licensing costs built into OSes shipping h264, devices built with HW decoders, online movies rented with it, etc.
And in exchange I get significantly poorer quality video.
http://www.extremetech.com/computing/142796-how-to-play-dvds...
Meanwhile those who doesn't want to pay for the priviledge of the better quality h.264 offers (and likely h.265 in comparison with vp9) will be able to use a free codec, hopefully one which will be standarised under HTML5 and thus supported across all HTML5 compliant software.
See, it works out for everyone.