Even though tokens are getting cheaper, I think the real killer of "unlimited" LLM plans isn't token costs themselves, it's the shape of the usage curve that's unsustainable. These products see a Zipf-like distribution: thousands of casual users nibble a few-hundred tokens a day while a tiny group of power automations devour tens of millions. Flat pricing works fine until one of those whales drops a repo-wide refactor or a 100 MB PDF into chat and instantly torpedoes the margin. Unless vendors turn those extreme loops into cheaper, purpose-built primitives (search, static analyzers, local quantized models, etc.), every "all-you-can-eat" AI subscription is just a slow-motion implosion waiting for its next whale.