This is a big HN LLM discussion divide. I am in the same no-specs work background camp, and so the idea that the humans who input that into dev teams are suddenly going to get anything out of an LLM if they directly input the same is laughable. In my career most orgs there has been no product person and we just talked directly to end users.
For that kind of org, it will accelerate some parts of the SWEs job at different multipliers, but all the non-dev work to get there with discussions, discovery, iteration, rework, etc remains.
If the input to your work is a 20 page specification document to accompany multi-paragraph Jira tickets with embedded acceptance criteria / test cases / etc, then yes there is a danger the person creating that input just feed it into an LLM.