The argument Apple is making from my understanding is that to comply with the law the system must allow other browsers and have a system setting of the default browser.
Currently PWA's open in an app that wraps Safari's engine to display the content and provide features but is not normal Safari. They interpret this to violate the browser choice law.
Their solution is to turn that feature off and go back to the icon just spawning the system default browser just like any link since that feature already existed.
To support true PWA's they probably have two choices:
1. Implement a standard WebView API that any engine can support then use that web view api for the PWA shell.
2. Do what Android seems to do and have a api that allows an app to create new launcher icons separate from the main app that starts the main app with parameters like url=https://pwa.com mode=pwa. Then if you create a PWA from Chrome it spawns Chrome if created from Safari it spawns Safari with whatever PWA UI they want. On Android it seems to make a little icon bottom right letting you know the parent app.
#1 is arguably more complex than #2, both are new api's for iOS that don't exist. #2 is on most desktop OS's like MacOS but not on iOS as far as I know.
Apples position is they don't want to put any resources in to creating a new api that could introduce new security surface area unless mandated to. Obviously their motives are not pure but it is a defensible position.
I think #2 would be a good feature adding flexibility to many apps, but the various shenanigans that apps could cause with that would need to be considered.
Currently PWA's open in an app that wraps Safari's engine to display the content and provide features but is not normal Safari. They interpret this to violate the browser choice law.
Their solution is to turn that feature off and go back to the icon just spawning the system default browser just like any link since that feature already existed.
To support true PWA's they probably have two choices:
1. Implement a standard WebView API that any engine can support then use that web view api for the PWA shell.
2. Do what Android seems to do and have a api that allows an app to create new launcher icons separate from the main app that starts the main app with parameters like url=https://pwa.com mode=pwa. Then if you create a PWA from Chrome it spawns Chrome if created from Safari it spawns Safari with whatever PWA UI they want. On Android it seems to make a little icon bottom right letting you know the parent app.
#1 is arguably more complex than #2, both are new api's for iOS that don't exist. #2 is on most desktop OS's like MacOS but not on iOS as far as I know.
Apples position is they don't want to put any resources in to creating a new api that could introduce new security surface area unless mandated to. Obviously their motives are not pure but it is a defensible position.
I think #2 would be a good feature adding flexibility to many apps, but the various shenanigans that apps could cause with that would need to be considered.