The very first assumption I made when I started thinking about the industry of getting and distributing apps was that it is illogical that we use an app to buy and install apps. In my opinion it is, to some extent, against the nature of things that we get some kind of items using an item of this kind. In fact, it is like we would somehow buy cars from withing a car or get ovens from within an oven rather than from a home appliance store. Hence, since the platform used for getting apps should not be an app, it neither should look nor behave so.
From my point of view, it indeed is right to install apps through a native interface like it works on iOS or Android. Nevertheless, the interface should not be an app, exactly like the Web, which enabling to share and browse online documents is not a kind of such a document at all. Moreover, such an interface should not be a kind of a business, even more so with a full monopoly on the market.