Let me start this assertion with a caveat: I have no data to substantiate my claim other than personal observation. But with that out in the open, I have no reason to believe that my personal observations are not representative of the IT job climate today. I am interested in getting others' opinions.
It seems to me that the average tenure of IT managers today is longer than the average IT foot soldiers'. An optimist's view on this phenomenon may be that managers are managers because they have a greater stake in the success of the organization, thus they tend to stay longer to realize some personal success. An argument can be made that managers either have a proven record of commitment to the organization's goals or that they have compensation incentives like stock options. A record of commitment is an emotional thing, and many managers who have worked their way up through the ranks probably have this. I call these emotionally tied managers. Compensation incentives, while not exclusive to new managers, are less emotional but no less a factor in why people stay with a job. I call these financially tied managers.
But cynic's view on IT managers' greater tenure could be that IT managers have fewer alternative job choices. While not always the case, many IT management positions require people to move away from their technical pasts. In our fast-paced environment, 18 months away can be a signifcant gap in terms of what changes. If one is an emotionally tied manager, this will not matter. They will stay with the organization through thick and thin because they deeply believe in the mission. But if one is a financially tied manager, the desire to stay with the organization during difficult times is less. But why don't these managers go elsewhere?
This brings me to my assertion. The reason IT managers may stay longer is that their ability to find new opportunities with comparable compensation is diminished.
More to come on this.