> tell me then, how exactly would this work as new features are developed - do all apps have to be static in functionality indefinitely?

Can you give an example of a "new feature" that you think would be stymied by this?

> how would it work with group chats where you can add and remove people arbitrarily?

I don't quite understand what issue you're pointing to. I'm not sure if you're unsure of how e2e encryption works or something else. Can you ask your question again with more specificity?