Apple did release the iPhone 16 in September 2024 with its broader Apple Intelligence branding, but the core scenario Sacks described never materialized:

• The advanced Siri overhaul based on large‑language‑model tech that was advertised alongside iPhone 16 was delayed to 2026, not shipped with iPhone 16. Apple executives and reporting (e.g., Bloomberg, summarized by MacRumors and others) note that the personalized, LLM‑driven Siri features slipped to an iOS 26.4 release in spring 2026 after quality problems, despite being used in iPhone 16 marketing. (macrumors.com)
• Instead of relying solely on an Apple‑built on‑device LLM, Apple is now planning to power major parts of revamped Siri with Google’s Gemini models running in Apple’s Private Cloud Compute, handling planning and summarization for Siri with a target around March 2026. That means the Siri upgrade is not purely on‑device nor purely Apple’s own model, contrary to the prediction’s premise about "rolling their own LLM" and not sharing data with third‑party LLMs. (androidcentral.com)
• On the demand side, analyst work from UBS finds that last year’s iPhone 16 and its Apple Intelligence branding did not spur a widespread upgrade cycle: the average iPhone in use (outside China) remained about 37 months old, and UBS explicitly concluded there is “no groundbreaking AI use case” and no significant AI‑driven sales boost, contrary to expectations of a massive upgrade wave. (barrons.com)
• Broader coverage of Apple’s 2025 software cycle similarly describes investors as underwhelmed by Apple’s AI progress and skeptical that current AI features will drive a major iPhone upgrade boom; Apple’s market cap fell on news of Siri delays, and analysts characterized updates as incremental rather than super‑cycle‑inducing. (businessinsider.com)

Given that (1) the exact condition Sacks specified—an iPhone 16 with a working, Apple‑only on‑device LLM powering Siri—still hasn’t occurred, and (2) the actual iPhone 16 + Apple Intelligence launch has not led to “everyone” upgrading or a clearly massive AI‑driven upgrade cycle, the prediction about a huge iPhone 16 AI upgrade wave is best judged wrong based on the real‑world outcome to date.