Here's an interesting perspective from Jeremiah Dillon the "apps guy @google".   He's saying or intimating installed apps are not the future for mobile, not if the developing world is to be any guide.

That may come across as unintuitive to most Americans.   A lot of us are addicted to installed Facebook, Snapchat and twitter apps.  But if you consider that on the desktop we migrated from installed window apps to web, then it shouldn't come as much surprise mobile is going the same way.