Who says anything about old models? What we're seeing is that as the frontier models get better, we get cheaper, better small models that leverage the advanced but cost a fraction. At the same time, hardware provides morez cheaper options. Sometimes far faster options too (e.g. Cerebras).

In terms of price, I can get 1m output tokens from Deepseek for 40 cents vs. 25 dollars for Opus, and a number of models near the 1-2 dollar mark that are increasingly viable for a larger set of applications.

Providers will keep running those cheaper models as long as there's demand.