So in corporate software development, I think LLM can readily reduce the needed headcount.
One is they ask employees to generate tons of procedural documentation that no one will ever ever read. Management will look and see a linked document hundreds of pages long and be satisfied that it was created, but never once will it ever be used by another developer. It's what managers imagine developers want of each other and so they force it, and developers have to satisfy this misconception while also providing what the developers need. Mountains of tedious garbage nonsense that looks vaguely right, congratulations, that is 100% in the LLM wheelhouse.
Another is having a team of junior devs that the senior devs would favor a small junior team because that quantity of junior devs are more work and less useful, but execs think an army is what is needed, when you just really want a nimble little team. AI is the marketing to make the business folks true believers.
The core people are still needed, but a lot of 'fluff' that perhaps should have already been gone can now be rationalized away.