What you describe is how iOS was first released. Anyone who wanted to build an app would use progressive web apps. Every native app was controlled by Apple only

What you describe is how iOS was first released. Anyone who wanted to build an app would use progressive web apps. Every native app was controlled by Apple only. This was loathed by developers and corrected in a later release. Given the steady recurring posts here on HN and elsewhere about hoping that Apple will open up to third-party app selections for email/browser/etc. someday, suggesting that Apple control the only Covid app on their platform is contradictory to that goal.