Speaking for myself, LLMs are reasonably good at writing tests or adapting existing structures, but they are not very good at doing what I actually want to do (design, novelty, trying to figure out the very best way to do a thing). I gain some productivity from the reduction of drudgery, but that's never been much of a bottleneck to begin with.
The thing is, a lot of the code that people write is cookie-cutter stuff. Possibly the entirety of frontend development. It's not copy-paste per se, but it is porting and adapting common patterns on differently-shaped data. It's pseudo-copy-paste, and of course AI's going to be good at it, this is its whole schtick. But it's not, like, interesting coding.