Earlier quoted context omitted.
> iOS/iPadOS does allow you to have one code base that dynamically responds to screen sizes. But almost always the experience for iPad users is terrible. are you saying the tools aren't there for developers to create equally pleasing (mutatis mutandis) apps, or simply that the developers aren't able to create equally pleasing (mutatis mutandis) apps? Or that designers can't grok the mapping between their equally plea…
There is no tool that can scale a mobile app to tablet size whilst maintaining a great UX. You need to optimise for the particulars of each device.
Our UI for the iPad was a completely separate one. The core code was shared via various internal libraries, but the UI was entirely different. Adding a feature to iPhone required one entirely separate set of code compared to the iPad app. The app was a universal binary though and one app ran on both device types.
This was, at the time, an absolute requirement. There was no way to scale the app from iPad to iPhone in such a way that it would give a great experience on both iPhone and iPad. It just wasn't possible to give an excellent app.
I've long since left and the app does seem to be written in SwiftUI now and seems to be one shared codebase. But I wouldn't say it's as good as it was previously.