And it's going to be done piecemeal, not all-at-once. Someone will figure out a way to get an AI to do _one_ thing faster and cheaper than a human and sell _that_. Maybe it's automatic test generation, maybe it's automatically remediating alerts, maybe it's code reviews. The scope of work of what a software developer does will be reduced until it's reduced to two categories:
1) Those tasks that it is still currently only possible for a human to do. 2) Those tasks which are easier and cheaper for a human to do.
You don't even really need to think about LLMs as AIs or conscious or whether they pass the turing test or not, it's just like every other form of automation we've already developed. There are vast swathes of work that software developers and IT people did a few decades ago that almost nobody does any more because of various forms of automation. None of that has reduced the overall amount of jobs for software developers because there isn't a limited amount of software development to do. If you make software development less expensive and easier than people will apply it to more tasks, and software developers will become _more_ valuable and not _less_.