And while the kind of errors hasn’t changed, the quantity and severity of the errors has dropped dramatically in a relatively short span of time.
I mean that seems wild to say to me. Those architectures have documentation and aren't magic black boxes that we chuck inputs at and hope for the best: we do pretty much that with LLMs.
If that's how you optimise, I'm genuinely shocked.
In my experience, even simple CRUD apps generally have some domain-specific intricacies or edge cases that take some amount of experimentation to get right.
From my experience, even building on popular platforms, there are many bugs or poorly documented behaviors in core controls or APIs.
And performance issues in particular can be difficult to fix without trial and error.