Most devs aren't very good. That's the reality, it's what we've all known for a long time. AI is trained on their code, and so these "subpar" devs are blown away when they see the AI generate boring, subpar code.
The second you throw a novel constraint into the mix things fall apart. But most devs don't even know about novel constraints let alone work with them. So they don't see these limitations.
Ask an LLM to not allocate? To not acquire locks? To ensure reentrancy safety? It'll fail - it isn't trained on how to do that. Ask it to "rank" software by some metric? It ends up just spitting out "community consensus" because domain expertise won't be highly represented in its training set.
I love having an LLM to automate the boring work, to do the "subpar" stuff, but they have routinely failed at doing anything I consider to be within my core competency. Just yesterday I used Opus 4.6 to test it out. I checked out an old version of a codebase that was built in a way that is totally inappropriate for security. I asked it to evaluate the system. It did far better than older models but it still completely failed in this task, radically underestimating the severity of its findings, and giving false justifications. Why? For the very obvious reason that it can't be trained to do that work.