A price index snapshot from December 2025 gives us market pricing and usage dynamics, but it barely scratches the surface of why programming model leadership moved so rapidly across the year.
The real trigger for shifting models—from Claude Sonnet 3.5 to 4.5, for example—is the demonstrable, immediate peak performance that new versions deliver.
People aren't changing their tools because of a historical data point; they're chasing the upper bound of what's possible, the full expression of value that makes their work better right now.
It’s about unlocking the highest possible payoff in code generation or debugging efficiency, not just what was captured on a chart months later.