This is the fundamental problem with all of these hypothetical new devices. If you assume you can come up with some new UI or innovative interaction model, maybe it’s purely voice or whatever else, then you have to ask if this could just run on a phone.

Modern smartphones won’t be supplanted by tech that could just run on a phone. That doesn’t make any sense. For any new tech to take off and replace phones, it has to provide something that isn’t simply additive to the phone. Otherwise, it just makes more sense to build it into the existing phone.

“A phone, but it has AI and no apps” isn’t even additive. It’s purely a loss of functionality.