I think they need to focus more on encouraging developers to get into making Apps for their platform.

In my opinion, we don't need another platform to learn - you can see how many people agree with me when you look at how prevalent web > native technologies are right now. PhoneGap, ReactNative, NativeScript.

If Microsoft decided to focus on Edge, not as a token "we still make browsers" gesture, but with a genuine interest to innovate.

They focused on web technologies, providing native support for web within their operating systems. Support in ways other manufacturers haven't.

Imagine if their app store was a place where you could publish a progressive web app (along side their current apps).

How low would the barrier of entry be then?