I'm not an expert on why teachers leave the classroom, but in my career of over 30 years I have seen many who have left, and believe me, they have not left because their talent has gone unrecognized.
I've seen teachers become librarians so they can avoid marking papers and doing work at home. I've seen them become guidance counselors because they couldn't control a classroom of 34 students. I've seen them become administrators for this same reason, and for money and for power. Often, these were teachers were the most incompetent teachers in the building.
The real talented teachers I know never left the classroom. They knew the only ones who would ever recognize and appreciate their skills were the children they dealt with every day. The most they ever hoped for was a little respect from their supervisors.
Stories like this one, on Gotham Schools, make me sick. These indivduals are there for themselves, not the kids. There is nothing wrong with supporting teachers, but the idea that this is needed to keep them in the classroom is wrong. My guess is a program like this is only a resume builder for those who take it.