Why do you feel he did NOT show step by step to reach the same conclusion and all these can not be understood by common man?
There is something called surrender
The greatest stumbling block in surrender is the over analytical mind.
In fact the common man might actually grasp jnaana faster than a scientific mind which just wont shut
The mind refuses to surrender. That is the only issue. That is why it invents theories like ‘ I am only a beginner’, ‘Realisation is far away in the distant future’, ‘ I must do this practice and that practice and progress slowly’ and so on and on. It is a cunning way to continue its existence. It will never heed genuine masters who point to Realisation here and now. Instead it will run after the dime a dozen street corner gurus who will keep it happily engaged in doing something or the other for a lifetime.