I would expect from a developer's perspective it makes sense to stick with Apple's mechanism until ARR * 0.30 = whatever it costs to run your own solution. (More power to you if you're the developer who can do that from the start, but that won't be most people.) I wonder, though, if the slow siphon becomes more obvious if it's attributed, in a customer's credit card statement, to [Game Co.] instead of [APPL]. I won't be sad if fewer people spend money on those types of games.