i don't have rigorous data at hand, but browsers and mobile hardware are now good enough that most apps are just fine being developed using cross-platform web tech rather than java or swift. plus, apps no longer attract and retain users as they once did (we're past the hype cycle). native mobile, as a result, has retreated to domains where the tighter integration has benefits, like games, health, IoT, etc. even apple is loosening its iron grip over its app store as the tradeoff between integration and flexibility no longer makes sense for most apps. apple now focuses more on content and on integrating more functionality into iOS itself because of that.