^The Android and Apple appstores each contain about 2,000,000 apps.
Compare to Steam, which has fewer than 10,000 games. And even on Steam people complain about the "indiepocalypse" where it's harder and harder to make it every month.
If there's 2 million apps in the store, there's no way in hell someone is going to randomly stumble upon your game. You need good reviews, marketing, word of mouth, etc.. Generally there's a feeling that the app store owners could do more to surface interesting games, but that's a difficult thing to do. As it stands, the rich just keep getting richer. The AAA F2P garbage stays on top because they can afford millions in advertising.