Neither Apple's nor Google's announcement says Siri will use Gemini models. Both announcements say, word for word, "Google’s technology provides the most capable foundation for Apple Foundation Models". I don't know what that means, but Apple and Google's marketing teams must have crafted that awkward wording carefully to satisfy some contractual nuance.
Direct quote from their joint statement: "Apple and Google have entered into a multi-year collaboration under which the next generation of Apple Foundation Models will be based on Google's Gemini models and cloud technology. These models will help power future Apple Intelligence features, including a more personalized Siri coming this year."
Source: https://blog.google/company-news/inside-google/company-annou...
I think Apple would also still like to publicly say it's Apple's model, not Google's.
Apple likely wants to post-train a per-trained model, probably along with some of Google's heavily NDA'ed training techniques too.
> "Google’s technology provides the most capable foundation for Apple Foundation Models"
Beyond Siri, Apple Foundation Models are available as API; will Google's technologies thus also be available as API? Will Apple reduce its own investment in building out the Foundation models?
Check again: https://x.com/NewsFromGoogle/status/2010760810751017017?s=20
"These models will help power future Apple Intelligence features, including a more personalized Siri coming this year."
Direct quote from Google themselves:
"Apple Intelligence will continue to run on Apple devices and Private Cloud Compute, while maintaining Apple's industry-leading privacy standards."