The difficulty with that argument is that Apple has gone out of their way to make webapps second class citizens. PWAs can't do everything installed apps can.
But that's not the point - the point is, sandboxing largely solves these issues without the need for restrictions on side loading, restrictions to a single app store or similar abuses of consumers rights.
Apple should build a better sandbox, the idea that "private APIs" exist and the only thing stopping them from being used is a basic string search on the app store review is pretty horrifying.
And that's before we get into resource usage.