In addition to the pay issues mentioned above, there's another challenge that IT trainers face: when you're training, you aren't doing. It's difficult to keep your skills current, if all you do is deliver training. Technical audiences expect trainers to be subject matter experts as well as trainers, and that combination is very difficult to find. So most training is delivered by SMEs who don't understand adult learning and classroom dynamics, or by experienced trainers struggling to establish their credibility with a new/updated subject that they haven't done real-life projects with in the field.