Why is the iOS app not open source?

[Michael]

Why the Android App is not open source?

The desktop version is open source. Completely. If you want an open source mobile client, feel free to create one. There’s absolutely no need to use the paid cryptomator apps if you don’t trust them only because they are not open source. I totally disagree with your argument that most satisfied users pay for open source apps. There is a reason why so many open source projects are ending because of financial reasons.