If you currently work in an office, think of how many days in a week you phone your IT department to report a technical problem. Then think about how many other people in the office do the same on a regular basis. There's a lot of work, a lot of demand, and not that many people well positioned to do it. We all use computers. Very few of us really understand what makes them tick.
If you could learn that knowledge, you'd be in demand from the moment you acquired it. Think bigger than answering helpline enquiries, although you can easily get into the six-figure range as the head of a busy IT department. Companies need advice on hardware, and software, and infrastructure; especially when they're setting up new premises. You could be the person supplying that advice, and your staff could be the people fitting it.