BB10 needs to have Google Play at any cost.
If there is a chance BB10 can survive, that will be with Google Play. No other way it can survive. BB needs to go to Google and pay whatever it takes so you can install apps from google play without sideloading. At any cost!!
The big problem with BB10 is with little tiny local apps from around the internet that only get uploaded to Google Play and iTunes. And those apps, most of them, could run flawesly in BB10 if you only could install them (like any other folk) from their webpage or their QR code.
Having native apps and a Shop for native apps is totally congruent with what I am saying. But I am pretty sure That is the blocking problem they need to solve right now.