Never underestimate the power of what is deemed to be out-of-date information! A few years back I responsible for infrastructure operations for a global organisation. We had so much legacy kit it was unreal! When issues hit the only route was to roll your sleeves up and get stuck in to the Interwebs!

Also I imagine, like myself there are a lot of people out there at the moment who are looking to retrain/learn more. I studied the CompTIA A+ syllabus a few years back for a job interview and that covers some of the old tech.