Interestingly, one of the greatest mathematicians of all time, Andrey Nikolaevich Kolmogorov, spent quite a lot of time teaching in schools, and writing textboo

Interestingly, one of the greatest mathematicians of all time, Andrey Nikolaevich Kolmogorov, spent quite a lot of time teaching in schools, and writing textbooks and articles aimed at that level of audience. This was especially true later in his career. As arguably the greatest mathematician of his time, he inspired many Soviet mathematicians and physicists to make a lot of time for teaching in Schools. Paul Erdos also made a great deal of time to meet with students. More recently, Physics Nobelist Carl Wieman quit the US because his work on physics education wasn't being funded. Of course, these examples don't contradict your statement, but they do make one wonder what is possible.