Why subscriptions? A one-time purchase revenue graph, even for a moderately successful app, looks like this. Yet work required only increases in complexity — Pastel has had 40 multiplatform updates since it launched in 2020, including two system UI redesigns, and a whole new OS (visionOS).

One-time purchases just aren't sustainable, unless the product itself is also one-and-done — and that's just not possible on a moving target like Apple's OSes. Revenue can't be inversely proportional to time