You have suddenly taken my argument to the absurd. Under my assumption, this mathematician is likely to continue to pursue mathematics. Why would he have worked on the Riemann hypothesis if he had no true interest in math? In addition to that, he has shown that he is willing to tackle some of the greatest problems in mathematics. So, therefore, I assume that he will continue to publish and that the ideas published are likely to be very deep. Therefore, he is likely to continue publishing few papers, but very deep papers.