GPT-5.4 Changed Who Gets Cited in ChatGPT — And Most Brands Are Optimizing for the Wrong Model

New data from a 1,161-citation study reveals a 7x gap between ChatGPT's free and premium tiers. GPT-5.4 cites brand websites 56% of the time. GPT-5.3 cites them just 8%. Here's why most brands are optimizing for the wrong model — and what to do about it.