Obviously I don't know how the rest of the interview went, but the way you put it in the retelling makes it sound a lot like it was distracting from all the other reasons to hire you.

"How about that two million guy?" - "We hire developers, not libraries"

It might have been that they not only picked up the idea from the interview, but on top of that also did not hire you because of misplaced conditions. If that part came over more like "you can't if you don't", then it would be seen as a challenge: "sure we can". I think that just telling them that you have previously worked on link monetization and wrote a library about it would have been a much better interview strategy than dangling some made up number in front of their faces. As an interviewer I would fear that a candidate arguing like that would be prone to taking their regular salary as granted and renegotiate something on top for every quantifiable contribution.