FWIW, everyone and their dog (nVidia, AMD, ARM, Qualcomm, etc) announced support for VP8 when WebM launched in 2010 too (
http://blog.webmproject.org/2010/05/introducing-webm-open-we...). Yet, hardware accelerated decode is basically non-existant still, and accelerated encoding doesn't exist at all. Even though lots of companies did demos of hardware acceleration.
Part of the problem is that within 3 years Google had already basically dropped VP8 and moved onto VP9. That kind of churn doesn't go over well in the hardware space typically. For a variety of practical reasons, codecs aren't the type of thing you usually replace every few years. It takes more than a few years for really good quality optimized encoders (e.g. x264, LAME, etc) to be built.
