It's not even so much as the fact that many apps are built as spyware as their primary function, and the thing they're advertised to do is actually the secondary function, or 'wrapper' of the data mining function (i.e. a brick-breaking game that needs access to your storage, photos, messages, contacts, location, etc.), but the platform they are released on (Apple Store, Google Play) require their own frameworks that also perform data mining. So even if you are an app developer who values user's privacy and choose to not include functions that data mine, in order to release your app to a wide audience, your app will automatically include the tracking functions of the framework you are forced to use.