If you work on stuff that is at all niche (as in, stack overflow was probably not going to have the answer you needed even before LLMs became popular), then it's not surprising when LLMs can't help because they've not been trained.
For people that were already going fast and needed or wanted to put out more code more quickly, I'm sure LLMs will speed them up even more.
For those of us working on niche stuff, we weren't going fast in the first place or being judged on how quickly we ship in all likelihood. So LLMs (even if they were trained on our stuff) aren't going to be able to speed us up because the bottleneck has never been about not being able to write enough code fast enough. There are architectural and environmental and testing related bottlenecks that LLMs don't get rid of.