> If the code works, passes all relevant tests, is reasonably maintainable, and can be fitted into the system correctly with a well defined interface, does it really matter?

You're not wrong here, but there's a big difference in programming one-off tooling or prototype MVPs and programming things that need to be maintained for years and years.

We did this song and dance pretty recently with dynamic typing. Developers thought it was so much more productive to use dynamically typed languages, because it is in the initial phases. Then years went by, those small, quick-to-make dynamic codebases ended up becoming unmaintainable monstrosities, and those developers who hyped up dynamic typing invented Python/PHP type hinting and Flow for JavaScript, later moving to TypeScript entirely. Nowadays nobody seriously recommends building long-lived systems in untyped languages, but they are still very useful for one-off scripting and more interactive/exploratory work where correctness is less important, i.e. Jupyter notebooks.

I wouldn't be surprised to see the same pattern happen with low-supervision AI code; it's great for popping out the first MVP, but because it generates poor code, the gung-ho junior devs who think they're getting 10x productivity gains will wisen up and realize the value of spending an hour thinking about proper levels of abstraction instead of YOLO'ing the first thing the AI spits out when they want to build a system that's going to be worked on by multiple developers for multiple years.

I think the productivity gains of dynamic typed languages were real, and based on two things: dynamic typing (can) provide certain safety properties trivially, and dynamic typing neatly kills off the utterly inadequate type systems found in mainstream languages when they were launched (the 90s, mostly).

You'll notice the type systems being bolted onto dynamic languages or found in serious attempts at new languages are radically different than the type systems being rejected by the likes of javascript, python, ruby and perl.

> those small, quick-to-make dynamic codebases ended up becoming unmaintainable monstrosities

In my experience, type checking / type hinting already starts to pay off when more than one person is working on an even small-ish code base. Just because it helps you keep in mind what comes/goes to the other guy's code.

The ML world being nearly entirely in Python, much of it untyped (and that the Python type system is pretty weak) is really scary.

I'm certainly extremely happy for having an extensive type system in my daily driver languages especially when working with AI coding assistance — it's yet another very crucial guard rail that ensures that keeps the AI on track and makes a lot of fuckups downright impossible.

> You're not wrong here, but there's a big difference in programming one-off tooling or prototype MVPs and programming things that need to be maintained for years and years.

Humans also worry about their jobs, especially in PIP-happy companies; they are very well known for writing intentionally over-complicated code that only they understand so that they are irreplaceable