Thanks for this post, I hadn't seen the linked conversation when it happened. Here's my reading. The conversation blog post you linked begrudgingly points out that companies aren't sunk by bugs, technical debt, or inefficient development practices. If you have a good sales team and a product that people want, need, or will be forced to use, you can succeed even if you have to burn money on dev, ops, customer support.
However I think what this langchain conversation is about is overeager VCs and a product that maybe doesn't do anything we need. It's not that langchain is slow or hard to use; it's that we can just do this stuff with Python or whatever. I don't have enough langchain experience to substantiate these claims but I think that's what I'm reading here.