This is closer to the reality I'm seeing. Software engineers are well positioned to understand and deploy LLMs to solve problems, even in adjacent domains. One of the engineers I work with gave a short presentation yesterday. It was quite simple. He'd just taken a series of screenshots from our product and put it into a Claude desktop session with some pretty significant prompt explaining how the screenshots related to a particular user flow and what the desired changes we were thinking about making were.
Took about 45 minutes and produced a working mock that we could then play with and see if the UX felt right. It was surprisingly high fidelity, and while the code was entirely throw away, it helped a room full of people make decisions about how we wanted the tool to feel within the first couple of hours of thinking about the project. Designers bring a wealth of UX thinking to that discussion, but the process of creating the mock was done entirely by engineering.