Honestly you wouldn't need AI doing fancy things to drastically reduce the need for IT personnel. All you'd need is better quality IT products. There's a lot of wasted work spent dealing with bugs, poor quality hardware and drivers, and terrible design choices. Too many developers and hardware vendors opt to create shoddy gimmicky products that don't work, and then IT has to spend hours and hours trying to make it work.
For example, I remember when iPhones first started making their way into the workplace, and it cut out a bunch of work for my department at the time. Instead of supporting crappy Blackberry and Windows devices, employees suddenly had a smartphone that was pretty reliable and easy for them to use, and didn't require a bunch of IT intervention. (I'm sure that example will be a little controversial, and someone will want to say "Nah, Blackberries were awesome and iPhones are stupid!" but this was my real-life personal experience and not an ideological argument about your feelings about Apple.)
If Microsoft would just fix their products and make them work sensibly, it'd cut out a lot of the things my department needs to work on and figure out.
Now there's also the question of what jobs improvements in IT are likely to eliminate. Better products would reduce the need for some technicians and support people, but I don't expect that products will get less stupid and gimmicky in the next 10 years. I fear they'll get worse. AI may improve monitoring and response, but you'll still need someone to evaluate the AI products, figure out which ones to use, make a business case for buying one, figure out how to implement it, and then keep track of it and troubleshoot areas where it doesn't do what it's supposed to.
And I think it's also worth noting that if you make an AI that can do good security monitoring and response, that may displace some low-level security monitoring employees, but the biggest impact will probably be to enable proper monitoring by companies who don't currently do it, or don't do it well. I think a lot of the AI coming in the next few years will do that sort of thing. It'll provide better security monitoring for companies who don't currently do a good job at security monitoring. It'll tag files with metadata that otherwise would require someone to manually assign, but for companies that wouldn't currently pay someone to sit around tagging files.
So you're right, I don't think IT workers should be concerned about AI replacing their jobs in general. AI may replace human work involved in clear and discrete tasks such as IT monitoring and real-time response, receiving calls and routing them, analyzing trends and generating reports, but in a broader sense I think we're safe. Not just because management is bad at understanding what they want, but because developers are terrible at building things. If Microsoft can't make Windows Update work reliably and without problems, what are the chances that they'll make an AI that can run whole IT departments without people in the loop? AI isn't that smart, and the businesses that are developing the AI aren't very smart either.