Some good responses in here, but I see a lot of people saying that this thing won't be a threat to Apple. That's probably true, but we should also remember one thing from the past:
Smugness like that and the "Imagine That" ad campaign showed a complacency that really bit Apple in the posterior, as the years passed. Ternus will most likely get the company moving forward with some direction now, instead of just inertia, but everything in the works at other companies - especially ones like Altman's which seem to have that "web 1.0" kind of burn money being thrown at it - really has to be considered.
Human interface is going to be the next big development in the OS field. This phone will have a screen but it may not be used for much other than watching videos, or single-instance data entry (phone numbers, for example). The OS in this phone may not just be the AI we're all unfortunately used to now, it may actually build the experience "on-the-fly". Like having a true personal assistant :"Make it so, Number One".
If thats the case, there's no need for an ecosystem at all. No need for apps to play music when you can say "play music that I like today", and the AI will build a music list from its perception of your attitude. No need for a contacts list when you can say something like "call the guy I spoke to last week about pressure washing the house". In fact there's no need for any kind of file manager or Finder when you can simply describe what you're looking for and the OS finds it. I think thats where everything is going. I don't like it but I can't stop "progress" any more than I can stand in front of a flood and block it.
I spoke here a few years back about a project Apple had on the front burner back in 2010-2011 that would have played well with this kind of thing. It was referred to as Project Magic, because it really would look like magic when the user implemented it. I didn't give out any details then because I was concerned that some Android folks might grab the idea and bring it back to Sauron, and now with AI scraping every forum and public square - and a lot of private ones as well - I'm doubly concerned that someone like Scam Altman and OpenSore could make use of the concept. I don't know what's happened with the project because we're several years past when the technology caught up to the concept.
Maybe they're waiting for Siri.