In theory yes, but in practice I think people who want to make a good amount of money don't work in these jobs, or at least not for long. For instance, you aren

In theory yes, but in practice I think people who want to make a good amount of money don't work in these jobs, or at least not for long. For instance, you aren't born as ultra-specialist. You get there by dedicated work and the goal to stick to that kind of task. People who want to earn money know a little about a lot of different things. About the middle management I can only suggest to read the Gervais Principle. They may be mostly the people who are not smart enough to get to the top and not socially skilled enough to job-hop easily enough.