I think it comes down to being a manager basically sucks. A lot of people, all other things equal, would rather not do it.
Think about it, a manager is fundamentally someone who has to deal with everyone's problems all day long. The one reason many people do it is because it is an obvious path to better pay in many companies. Otherwise who would voluntarily deal with other people's problems all day long?
That isn't to say I think they are necessary but that if you have a crappy position the obvious way to fill it is via higher pay.
Think about it, a manager is fundamentally someone who has to deal with everyone's problems all day long. The one reason many people do it is because it is an obvious path to better pay in many companies. Otherwise who would voluntarily deal with other people's problems all day long?
That isn't to say I think they are necessary but that if you have a crappy position the obvious way to fill it is via higher pay.