What you really want is the ability to sideload apps without the App Store. Then you'd get your alternative browser rendering engine as well as tons of other useful apps that will never be available. Apple can do their best to make it difficult and warn users of the risks but it should be possible.
> What you really want is the ability to sideload apps without the App Store
Not really. The curation and verification of the App Store is a feature. I don’t want to have to download a must-have sideloaded Google app for work that snuzzles up all my data to Mountain View.
If not using the App Store is an option, then a developer could just not use it and you could be forced to get an app from an insecure place. That defeats the purpose of the App Store.
Developers will want to use the app store because they'll want to reach a broad userbase, just like on Android with the play store. (The Play Store has lots of scummy apps, but that's down to Google doing an awful curation job.)
On Android, It can install apps from anywhere if user set a config. But most apps are still on Google Play Store so rarely need to install app from external sites/apps. I expect similar thing happens if Apple allows it.
