Well, the author specifically mentions the puzzle of how it produces nicotine. Nicotine was first identified and isolated as a chemical in 1828, based on a quick google. So, no one was wondering about nicotine production before then because they didn’t know what it was.

How exactly would they ask that question 10,000 years ago if they didn't know what molecules were, much less nicotine?

>Nicotine was originally isolated from the tobacco plant in 1828 by chemists Wilhelm Heinrich Posselt and Karl Ludwig Reimann from Germany, who believed it was a poison.[210][211] Its chemical empirical formula was described by Melsens in 1843,[212] its structure was discovered by Adolf Pinner and Richard Wolffenstein in 1893

30 seconds on Wikipedia would have given you context of when the separation of nicotine occurred. Kind of hard to guess how tobacco plants make nicotine when you don't know what it is.

Seems like we're confusing "what" with "how".