All of the knowledge "hoarders" that I have ever met are insecure people. Not in knife-making, but in all walks of life.
I used to love to watch Arnold Palmer, but at the time had no appreciation for the millions of practice balls he had to hit before he became a master. Same goes for Julius Erving on the basketball court. He would do a little move, the poor defenders would end up on their butts (with no contact at all), and he would score. I would go outside to try that, because it looked easy, and I would be the one on my butt - every time!
It takes a real master to make something very difficult look easy. The masters usually have talent, and also many years of blood, sweat, and tears behind them. They are generally pretty secure people, and for good reasons.