> Or is it because each firm now develops its own LLM stack? My money would be on this. Custom LLM frameworks are relatively easy to build for experienced devs

> Or is it because each firm now develops its own LLM stack? My money would be on this. Custom LLM frameworks are relatively easy to build for experienced devs, and probably less work than adapting an off-the-shelf one, so making a custom framework is a no-brainer. Anyway, I think LangChain and similar projects have been mainly useful as proofs-of-concept and by creating awareness.