I think it is because the EU is requiring broader access to the deeper layers that Apple doesn’t want to give.

EDIT: by broader I mean all apps the user installs on their phone.

There’s a difference between Apple being able to swap out the model in code and Apple letting end users choose which model to use.

This appears to be the current feature prototype intended for the EU and potentially China. Apple has chosen not to release the new Siri AI in the EU because our Digital Markets Act requires them to allow interoperability. I.e. that users be allowed to choose another AI provider.

Ostensibly they'll activate this in the EU when it's ready. Given the current functionality, it looks ready (or close to being ready). My guess is it is ready and Apple is doing their usual negotiation tactics with the EU to see who blinks first.

Possibly, but certainly the EU.

I don't disagree, but I do feel the need to point out this was not Apple's plan A. Luckily for them they have so many tools and options at their disposal, that they are able to massively fail at developing their own models and still end up in a good position.