> I've written 100s of thousands of lines of difficult code.

How do you know it's difficult if you say you don't understand it?

> Anyway all of this reads like someone who is not actually using LLMs to build software or hasn't tried them in a while.

I run all the "latest and greatest" models the moment they become available to me. The amount of insanely bad code they produce remains largely the same, and largely in the same areas. And it cannot be caught by tests unless you know that bad code is there and end up with extremely bad tests anyway. I wrote about it here: https://dmitriid.com/adding-to-i-dont-read-ai-code-discourse

Main one is, of course, "to get a record from a database read all records from it, and filter in memory".