I think that in general there is a big difference between javascript/typescript projects big or small and other projects that actually address a specific project domain. These two are not the same. The same claude code agent can create a lot of parts of a function web project, but will struggle providing anything functional but a base frame for you to build on if you were to create a new SoC support in some drone firmware.

The problem is that everyone working on those more serious projects knows that and treats LLMs accordingly, but the people that come from the web space come in with the expectation that they can replicate the success they have in their domain just as easily, when oftentimes you need to have some domain knowledge.

I think the difference simply comes down to the sheer volume of training material, i.e. web projects on github. Most "engineers" are actually just framework consumers and within those frameworks llms work great.