But the devs here are all very experienced senior-level engineers. Perhaps that's why we aren't seeing any gains?
My experience was that it was about as useful as searching Google and Stack Overflow without knowing what a good answer looks like. You copy and paste a lot of code, a lot of it works, but inevitably, something breaks and you have no idea why. So you still have to go back to "the hard way" of reading the documentation and building an understanding.
I'm sure things will improve over time, especially for products built specifically for code generation, but my first and second impression is that so far, LLMs don't actually lower the bar for junior programmers.
Otherwise you're suggesting that these senior devs are using a tool which provides no value whatsoever which seems unlikely.
I think many software developers have this romantic, idealized notion that their entire job should be furiously typing code into a computer, and that anything else they have to grudgingly do is unproductive overhead.