But they're not.
There's a few confounding problems:
1. Actually using that hardware effectively isn't easy. It's not as simple as jacking up some constant values and reaping the benefits. Actually using the hardware is hard, and by the time you've optimized for it, you're already working on the next model.
2. This is a problem that, if you're not Google, you can just spend your way out of. A model doesn't take a petabyte of memory to train or run. Regular old H100s still mostly work fine. Faster models are nice, but Gemini 3 Pro being 50% of the latency as Opus 4.5 or GPT 5.1 doesn't add enough value to matter to really anyone.
3. There's still a lot of clever tricks that work as low hanging fruit to improve almost everything about ML models. You can make stuff remarkably good with novel research without building your own chips.
4. A surprising amount of ML model development is boots on the ground work. Doing evals. Curating datasets. Tweaking system prompts. Having your own Dyson sphere doesn't obviate a lot of the typing and staring at a screen that necessarily has to be done to make a model half decent.
5. Fancy bespoke hardware means fancy bespoke failure modes. You can search stack overflow for CUDA problems, you can't just Bing your way to victory when your fancy TPU cluster isn't doing the thing you want it to do.