Comment by quitit

While I can think of a few examples where they have done back ports given time (but not at launch). I still very much see this the same way as you do for Apple Intelligence. Firstly because they're unlikely to announce it for older phones unless they can get every model working well. Secondly because I notice they've been careful about which of the new AI upgrades are classified as Apple Intelligence, versus those which have been packaged into iOS 18 without fanfare.

I'll give an example:

The iOS 18 photos app, without "Apple Intelligence", still has an improved search function. This is driven of course by a new AI model that tags images with more detail and fidelity than earlier iterations.

However "Apple Intelligence" also features further upgrades to photo searching where a user can request images with highly specific details, expressions or interactions. The example they give is "Katie with stickers on her face", and beta testers have shown examples which demonstrate that other than just tagging individual objects, those items themselves are described and searchable. (E.g. The difference is like between being able to search for photos with a "dress", versus "a red dress", "a wedding dress", <person> "wearing polka dot dress", etc.)