> I have no data, but ES7 plans to support async/await, and Python 3.5 just shipped with it. I find it a strong signal already.

we're mixing up 2 different things here, the async package and the C# like async/await feature native to javascript. The async package while popular is certainly not more popular than promises.

> I find it a strong signal already.

Well cancel your signal because native browser APIs are returning promises:

https://developer.mozilla.org/en-US/docs/Web/API/MediaDevice...

async/await is powered by promises, it's crazy to say that promises are going away, they're becoming an even more fundamental construct in the language.