That's not how apple store works...
> The developer is required to grant Apple sole sales rights. The developer cannot sell their application
> through any other channel (or even give it away). The customer is therefore unable to purchase directly
> from the developer, they must purchase from Apple. Apple is the seller.
I'm sorry, but that's not correct.
You can have your application in other app stores. For example, Evernote is in the Android store, etc. But if it's a paid application, the price has to be the same across stores.
Now, you might be trying to say, that your IOS application is only available via the Apple Store.
Sure, I'll agree with that. But, for example, you can have FREE software. Is Apple selling you that?
Apple is a distributor. When you purchase "Avengers Infinity War" at your local Walmart, are you trying to tell me that Warner Brother's is selling you that DVD / Blu-ray? No you are purchasing it at Walmart.
Don't you think that Warner Brother's is taking a portion of the sale? (Hint, they are, but they are getting their portion upfront).