Human programmers have continuous assistance on every keystroke - autocomplete, syntax highlighting, and ultimately, also the compilation/build step itself.
For an LLM-equivalent experience, go open notepad.exe and make substantial changes there, and then rebuild - and let the compiler tell you what's your base rate of hallucinating function names and such.
In the 1990s, that is closer to what making software was like. There, one had an even more heightened awareness of how confident one was in what one was typing. We would then go to the manual (physical in many cases) and look it up.
And we never made up APIs, as there just weren't that many APIs. We would open the .h file for the API we were targeting as we typed into the other window. And the LLMs have ingested all the documentation and .h files (or the modern equivalent) so they don't have a real excuse.
But I use the LLMs all the time for math, and they do profusely hallucinate in a way people do not. I think it's a bit disingenuous to say that LLMs don't have that failure mode that people don't really have.
For an LLM-equivalent experience, go open notepad.exe and make substantial changes there, and then rebuild - and let the compiler tell you what's your base rate of hallucinating function names and such.