[Contributor to Aviary] Not many are building their own LLMs (though there are some like Bloomberg). But quite a few are experimenting with fine tuning.

One of the great things with LLMs is that they can (and are) fine-tuned with small amounts of data. In our previous work, we showed it cost as little as $7 to fine tune a model with 40,000 lines of text.

I don't think many will be rolling their own from scratch, because fine-tuning is cheap and effective, and there's value in owning your LLM stack.