> Apple could build it in a way that other model providers could safely and securely interface with the Spotlight index

How? How do you safely handover effectively every single bit of data on someone’s phone to any third-party company and preserve privacy?

Sure you can try and demand agreements from the third parties but will the EU see that as a move to limit competition?

Ignoring all other concerns it is a rather thorny problem.

I don’t think the EU would accept, and as a user I certainly wouldn’t accept, having to agree to a pop-up every time I used any feature that used any data on my phone that might go to a third-party AI.