Yet neither spreadsheets nor SaaS is defunct. They are just getting refined down to their actual use case. AI also has finite use cases, but are currently in the part of the hype cycle where all kinds of crap in thrown in regardless of whether or not it is really the correct solution.
Some day in the future, something new will come along and diminish LLMs in this same way, when everything that never should have been LLM-driven in the first place will move along to the new thing and get its chance to be done correctly.