The field of Information Retrieval has largely moved to multi-modal retrieval (search across video, audio, text), linked data, question-answering and so on. Bu

The field of Information Retrieval has largely moved to multi-modal retrieval (search across video, audio, text), linked data, question-answering and so on. But document retrieval (classic search as you describe it) is not a hot topic anymore. That does not mean there are not people working on constantly improving document retrieval: Google Scholar returns 17,800 results for "document retrieval" in 2018 and 34 results with it in title. So it is in widespread use but not the focus of the field, I would say.