Bullshit. I don't find this to be true at all. In my experience, "Masters" of any craft tend to be people who, while highly skilled, also recognize that one can never 'know everything there is to know', and that learning is, in fact, not a means to an end....It is an endless process.
I also find myself wondering why some people are so concerned with labels such as "master", and "true bonsai trees". I know its in our nature to label and categorize everything.....but in this case, what purpose does it serve?