Re: They tried to cheat their way out of payment system they knew upfront about.
There is a difference between a payment and a purchase when comparing to shops etc.
Apple's end of the so called in-app "purchases" is, in reality, and in practice, offering nothing more than a payment system/broker, taking a 900% greater cut for a commodity service. (30% versus the typical 3%)
Recurring billing, service upgrades etc do not involve any Apple infrastructure for what is just payment except what is being artificially enforced, at an artificial fee.
So you need to compare this with payment charges with other services that are 1-3%, not purchase margins.