A December 2025 price snapshot doesn't explain market leadership shifts that already happened earlier that year; that's interpreting an outcome as a cause without detailing the actual trigger.
Companies don't shift from Claude Sonnet 3.5 to 4.5 based on a future index; they consider immediate adjustment costs like rewriting entire API integrations and prompt libraries.
This isn't theory; it's weeks of development and testing to prevent system invalidation, much like when an OS update breaks custom drivers.
Until we get the operational action—the specific performance gains or critical bugs that forced a switch—an index is just data for a watchlist, not the real driver.