If the "self" is an illusion, and if (as is proven in the preliminary exercises of Dzogchen) looking for the mind, or the thinker, or the one who is looking can

If the "self" is an illusion, and if (as is proven in the preliminary exercises of Dzogchen) looking for the mind, or the thinker, or the one who is looking can provoke this kind of insight...what makes you think anyone would have to steal ancient wisdom to arrive at such a conclusion?