I see it moving to a situation where a consumer pays a monthly price and has access to all the apps they want to download. This is already happening to games (see humble bundle & EA Origin subscription).

Amazon are moving this way to an extent, at GDC 2016 the announced that you could publish your app for free on their app store for their line of tablets, and they would pay you per customer per minute of usage on your app.

Also, didn't exactly the same thing happen to music industry?

Now we can pay $0 for music, we just have adds interspersed between tracks.

The same thing will eventually happen to everything digitally distributable.