A&P mechanics are trained in a variety of disciplines. I can't think of any other training that provides the diverse knowledge A&Ps have — sheet metal repair, welding, hydraulics, piston and turbine engine, non-destructive testing and others. The list goes on and on,
That vast training and knowledge is why some A&P students never end up working on aircraft. They are recruited by other industries such as the railroad and amusement park industries.