Even the great beings of the past are obliged to go to school and learn everything anew when they return to earth. This may surprise you, but it is a law: all beings who incarnate on earth, whoever they may have been in the past, must begin their education and apprenticeship all over again.
What sets them apart from others is that they obtain great results very quickly, but everyone, without exception, must take up their work at the beginning again if their qualities are to manifest themselves in this lifetime.
If Mozart had not been born into a family of musicians who could give him the conditions he needed to learn and perfect the gifts he brought with him from the past, his genius would perhaps not have manifested itself so brilliantly. However great the wisdom and powers possessed by initiates in a previous incarnation, they must still work to regain that knowledge and those powers.
And if that is true for them, those who have yet to reach such a degree of evolution must work all the harder!