Porting vArranger to iOS is cool for sure, as vArranger is far ahead of arranger software available today for iOS
But to do that, I need to hire some iOS developpers etc... and not sure the work will be paid with the $5 app price
Although many apps are ridiculously cheap, there are examples of very expensive ones. One of them is „Turbosound“, an app for Alpine live music. Each single instrument costs around 50 Euros, so you can easily spend 500 Euros or more for a good selection of sounds. Apparently, some really interested musicians are willing to pay it.
So, for Varranger, I wouldn‘t think you couldn‘t charge a price that covers programming costs...