I conclude from all this that anyone who wants to make a satisfying living as an independent app developer should seriously consider only building apps based on sustainable revenue models. I suspect this means through consumable in-app purchases, like those in Candy Crush Saga or Clash of Clans, or through recurring subscription charges, like those in WhatsApp.
The marketplace has changed drastically over the past few years and I think we’re going to see more and more freemium apps, such as Arment’s Overcast. As for Edovia, it is quite possible that our next major releases will offer new features through In-App purchases.
I have always been against the race to the bottom and priced Screens accordingly. The freemium model (or at least the Charge-Less-For-Basic-Functionalities-And-Offer-In-App-Purchases-For-Pro-Features model) is now something to consider and perhaps, unavoidable on the long run.
Furthermore, I have grave doubts that any solo developer would have the capacity to ship and maintain either kind of business working alone. She would probably have to consolidate her business with other indie developers in the same position. The marketing budgets of the major competitors makes me doubt that even a consolidation strategy is tenable.
I’ve been pretty successful with Screens because I was able to hire excellent developers and designers. The app would not exist without them.