I believe you're mistaken. At the 55 minute mark in the stream, Craig Federighi announced Visual Intelligence, exclusively for iPhone 16. That's not the same as Enhanced Visual Search, which appears to be available not only for all iPhone and iPad models but also for Mac.
"Note: Visual intelligence with Camera Control requires Apple Intelligence and is available in iOS 18.2 or later on all iPhone 16 models." https://support.apple.com/guide/iphone/use-visual-intelligen...
Moreover, Apple Intelligence, and thus Visual Intelligence, is opt-in rather than opt-out.
> Then there’s the blog post that describes the privacy features fairly detailed from October 24 (Combining Machine Learning and Homomorphic Encryption in the Apple Ecosystem).
How many people read Apple's machine learning blog? I certainly don't.
> I think the feature went live in iOS 18.1
That's what we're speculating, based on some vague evidence, but I'm not sure anybody knows for certain.
> There’s even a post on Reddit from five months ago noting the toggle appearing in the beta.
You're seriously citing a single obscure Reddit post as evidence that this wasn't a surprise to the general public?