For me, if it stays exactly the same only updated with the latest data ingested it will still be useful for me in 5 years - that is unless something even better replace it.
Alternatively LLM’s will have gotten good enough that prompts can be general enough to not need tuned skills. I.e the average person can prompt well enough to get great results
"the input methodology will change" includes this.
There is absolutely zero basis to have any certainty about things like this.