I'm not talking about sharing state with your webserver, I'm talking about two apps on your phone sharing state directly with each other without ever leaving the device or becoming accessible to a third party.
Desktop operating systems have a slew of ways to facilitate this, and the mobile gatekeepers keep eroding them. They're also terrible at dependency management (a completely solved problem in real package managers), which discourages creating apps that depend on other apps.
There are still ways to do any given thing, but if you make it harder then you make it rarer.
> My understanding is the app permission model never asks for network access, so all "apps" are effectively web clients with a fancy UI.
At least for Android, not exactly: they still have to require network access (android.permission.INTERNET), and you can check if they have done that in the Play Store (description → Read More → App permissions). What changed is that the Store won't explicitly ask you to confirm you're OK with it when installing.
In any case, typical native applications didn't have to ask for network access either, that didn't make them all effectively web clients. Many of the mobile apps I have installed don't rely on a central service.
Example:
https://news.ycombinator.com/item?id=19521211
I'm not talking about sharing state with your webserver, I'm talking about two apps on your phone sharing state directly with each other without ever leaving the device or becoming accessible to a third party.
Desktop operating systems have a slew of ways to facilitate this, and the mobile gatekeepers keep eroding them. They're also terrible at dependency management (a completely solved problem in real package managers), which discourages creating apps that depend on other apps.
There are still ways to do any given thing, but if you make it harder then you make it rarer.