you sure? anynet+/hdmi-cec has been around since quite some time, most people just don't know about it as it's usually poorly documented and buried in not so user-friendly config menus.
Sometimes it doesn’t work due to manufacturer bugs. I have a TV that has a bug in their implementation on a specific series of theirs where it won’t turn on/off the TV, but volume does work via HDMI. From doing extensive research I’m not alone.