Comment by ndriscoll
Your point doesn't make any sense. The only reason Apple's store can have "all" the apps is that they are a monopolist and take steps to disallow anyone from selling apps through any other channel, so there cannot possibly be multiple storefronts with different selections like their is in any other context.
On Android for example, Play Store does not have "all" apps, or even most apps that I have on my phone. Because Play Store has mostly garbage. It's a surprise to no one that Steam's storefront has a different selection from Amazon or Epic or GoG in the same way that no one is surprised that Walmart and Target carry different items.
So "discovery" in your sense is basically "I ignore everything that isn't presented by this particular storefront", i.e. a complete lack of discovery.
If you think "the web has orders of magnitude worse discoverability than mobile app stores" makes no sense, then there's not enough common ground for us to have a productive discussion on this.