As much as I would like to agree with this, I think we should expect H.264 to be the de facto codec for quite a while longer. Consider the following:
* An industry research group's 2017 survey [0] showed us that most users still only stream at 720p and that will probably not change in the immediate term. When 4K is the norm, we'll have a glaring need for AV1.
* That same Harmonic 2017 survey also showed that most distributors don't plan to leave H.264 because it is serving their needs just fine.
* x264 only got to where it is today after nearly 10 years of active development. I remember how painful it was to encode H.264 with open source tools in the beginning. Most distributors will not want to take the plunge immediately into AV1 until x264-style stability and acceptance are imminent.
[0] http://www.streamingmedia.com/Articles/Editorial/Featured-Ar...