Where did you get that from? Cutoff date says august 2025. Looks like a newly pretrained model
- https://newsletter.semianalysis.com/p/tpuv7-google-takes-a-s...
It's also plainly obvious from using it. The "Broadly deployed" qualifier is presumably referring to 4.5
It's probably just a question of cost/benefit analysis, it's very expensive to do, so the benefits need to be significant.