Let's be honest though, no one is going through the trouble to port their app to Windows 10 only HTML and JS. I don't think MS has even talked about that stack at their recent developer conferences.
It's not a "sexy" stack to talk about, but I don't think it is going anywhere. There are quite a few Windows Store applications built on it, including several first party applications from Microsoft themselves. It's a quiet workhorse stack that does the job and gets out of the way. So quiet I don't think people often realize when an app is built on it.
The singular issue with electron is how fucking huge the simplest of apps have to be. I see desktop HTML/JS as a RUNTIME being a very near-future standard.
I'm sure electron has thought about it. It couldn't possibly be any bigger of a hassle than the java runtime.
For what it is worth, I agree. The web browser is a required component of operating systems these days and first class/"native" support for web applications is a standard that we should celebrate and encourage.
I don't think it is "sexy" to most developers right now because there are still a lot of developers that still cling to ancient "native" control toolkits, ancient ideas that web platform is already the main UI platform for the majority of user these days, and for whatever reasons dislike HTML and JS for application development. You see a lot of the complaints here on HN every time Electron or Cordova are brought up.
I'm sure Microsoft knows they don't get a lot of enthusiasm from a lot of developers for the native Windows 10 web stack, so I'm not surprised they underplay it at conferences. Those of us that do care know we can follow the Edge team blogs and know that UWP API enhancements benefit all three main stacks.