Observation/opinion 1: the average person does not make full use of their capabilities (in my opinion just about anyone can be trained to do just about anything a human can do, with enough time, the right instructor and a willing pupil)
Observation/opinion 2: it is not motivating to undertake tasks that are well below ones capability level*
Observation/opinion 3: techniques of automation and robotics are nowhere near eliminating all tasks that are below the capability of a well-trained human
Observation/opinion 4: it is possible to reduce the capability of a person through feedback that alters that person's perception of their capability
Even if it is the case that there is no deliberate/conscious action to lie to individuals about their capability, the structure of education systems has an equivalent effect.
*A great concern of mine (no doubt inspired by Marvin from H2G2) is that making AI intelligent enough to be able to handle all of our menial tasks will make it subject to the same aversion to menial tasks as humans.