Langchain was released in October 2022. ChatGPT was released in November 2022.
Langchain was before chat models were invented. It let us turn these one-shot APIs into Markov chains. ChatGPT came in and made us realize we didn't want Markov chains; a conversational structure worked just as well.
After ChatGPT and GPT 3.5, there were no more non-chat models in the LLM world. Chat models worked great for everything, including what we used instruct & completion models for. Langchain doing chat models is just completely redundant with its original purpose.
Langchain was before chat models were invented. It let us turn these one-shot APIs into Markov chains. ChatGPT came in and made us realize we didn't want Markov chains; a conversational structure worked just as well.
After ChatGPT and GPT 3.5, there were no more non-chat models in the LLM world. Chat models worked great for everything, including what we used instruct & completion models for. Langchain doing chat models is just completely redundant with its original purpose.