I spend all day talking to people shipping AI products and approximately zero of them actually use LangChain.
LangChain doesn't make sense for a ton of reasons, but the top few are the code quality being horrid, the scope being ill defined, and the fact that most of the tasks it does are better done with a prompt that was designed for your exact use case.
We're actually shipping "AI products" and love LangChain.
Your criticism doesn't line up with anything in my experience. Nearly all of the prompts you use are your own, and you can customize any of the prompts used under the hood for chains like routing.
LangChain doesn't make sense for a ton of reasons, but the top few are the code quality being horrid, the scope being ill defined, and the fact that most of the tasks it does are better done with a prompt that was designed for your exact use case.