Besides the new form factor, resizable apps are also meant to further bridge the gap between macOS and iOS right?

More than that, it forces iPhone-only devs to get with the program and make their apps usable on larger screens too.

I wouldn’t be surprised at all if next year they dissolve the iPhone/iPad distinction on the App Store altogether and maybe even remove the Catalyst toggle on the Mac App Store. If you make an iOS app, it’s also a full fledged iPadOS, macOS, and visionOS app too.

I certainly wouldn’t mind. On my Mac there are some needlessly heavy electron apps I’d swap out for their iOS counterparts in a heartbeat if that were possible, as well as some games that would run fine on macOS but their devs don’t tick the checkbox for unclear reasons.

> I wouldn’t be surprised at all if next year they dissolve the iPhone/iPad distinction on the App Store altogether

I hadn't thought about it but it makes sense and it makes me wonder how far this would reach throughout the rest of the OS. If the iPhone can fold out into an iPad Mini, will it get the rest of the iPadOS features? The iPad used to run iOS but they rebranded the version that runs on iPad to iPadOS to distinguish that it has a handful of unique features only for big screens, mainly pertaining to multitasking. But if the line is being blurred and iPhones will have big screens with multitasking, will they go back to just calling it iOS on all mobile devices?

You're just arguing about marketing. Apple has moved to a One device, one OS dichotomy they will not rethink because the foldable iPhone gets a version of the iPad's multitasking. And engineering-wise, when they moved the naming to iPad OS, nothing changed behind the curtain. The iPad still runs the same codebase it did before the marketing switch. They didn't fork anything.

I think they’re going to continue to make some features device-specific. They probably want to position the foldable iPhone as a midway compromise device rather than a full iPad and flagship iPhone replacement, targeting customers who prefer breadth over depth and capability when it comes to features.

At the very least, this is needed for iPadOS and macOS, since both have resizable windows.

I'm currently working on a responsive app in Swift and had to develop my own responsive layout system. SwiftUI simply isn't up to the task, except for one very specific, generic layout.

I'd guess that they're meant to bridge the gap between iOS and iPadOS, if anything.