Re: why focus on internal power
The Movie Series "Kill Bill" probably insulted every martial sensibility I had, yet it was hilariously wise. One character, Pai Mei, was not sequestered on the mountain to purify his shen with "marrow/brain washing exercises. He was there because he had become so specialized that he could not relate to other people.
In retaliation, he became hard nosed and unfriendly...downright mean spirited. He was not an ascended master. He was just a lonely old man who probably was silently hoping for the death he was given by such an "ungrateful student".