Odds of Hanging On
As with just about every job on the planet (except for maybe herding sheep), technological innovations are being applied to IT management. For example, there's software that will let a single person monitor, manage, and support a company's IT processes with the click of a button or the flip of a switch or, you know, simple mental telepathy. (That "mental telepathy" bit is a joke—or is it?)
What does this mean for you, oh wannabe IT manager? Well, some jobs in IT management will probably disappear as software innovations take hold, because why have a whole department of IT staff when you really only need, say, two? However, the jobs that go poof are likely to belong to less experienced employees.
The fact is, many IT managers possess a combination of skills, education, and experience that software is never going to be able to replicate. For these folks, IT management software is actually a blessing, because it allows them to deal with annoying and mundane tasks quickly so they can focus on the big, pear-shaped problems they're paid good money to handle.
In other words, don't be a peon in IT management. Shoot for the top, and you'll always have a job.