Where aliens, why do not fly and tell how they live about what they think. They will share their knowledge and really, what else they share with earthlings. We are not educated chocks. All the discoveries are given to us with difficulty, and their discoveries can be called with a stretch.
But we are definitely convinced that the foreign mind is much the development of us. He is able to perform miracles and not only. So maybe this is the reason. Do not come to us, because they are not interested in us. We do not reach their level.