Personally, i think this all boils down to making good plans and drawing deadlines to when you want to achieve them. This is something most people don't master throughout their careers thats why some people excel more than others.

Another factor that can affect this is that most people invest and create more than just one source of income for themselves when others solely depend on their salary hence giving them an edge over others.

For those that wants to make good profit, creating more than one source of income is the way to go.