There's hype and FOMO for sure and you're right that there's lots to learn from information retrieval work. But why be dismissive of the whole thing? People learning from past research and applying it in new contexts seems like a good thing and there's people (like https://x.com/bclavie and https://x.com/jobergum), who are legit experts in information retrieval and are showing how to apply it to RAG properly.