Yeah, they wouldn't. Marginal costs to app developers are effectively 0, so profits and revenue are synonymous.Thus prices are set to maximize revenue. If setting my IAP at $10 maximizes revenue, that's true whether the processing fee is 0% or 30%. Cost to consumer is determinant.
Now if I'm given the options of accepting App store payments at 30%, and let's say PayPal at 3%, I'm going to offer the customer a little discount to switch to PayPal. That too will be whatever discount maximizes profit. That wouldn't be too hard to determine with testing, and would depend on how easy the payment methods are and how much customers love the convenience/security of Apple's payment system.
For me as a consumer, if I got offered a 10% discount and had something comparably easy to use I'd probably go with it on small transactions. If I had to enter a credit card, I'm not going to bother on a $1 or maybe even $10 purchase for that little.
Now if I'm given the options of accepting App store payments at 30%, and let's say PayPal at 3%, I'm going to offer the customer a little discount to switch to PayPal. That too will be whatever discount maximizes profit. That wouldn't be too hard to determine with testing, and would depend on how easy the payment methods are and how much customers love the convenience/security of Apple's payment system.
For me as a consumer, if I got offered a 10% discount and had something comparably easy to use I'd probably go with it on small transactions. If I had to enter a credit card, I'm not going to bother on a $1 or maybe even $10 purchase for that little.