People have spent their whole lives training and refining MA, why miss out on their incredible knowledge and insight?
I dont believe you can learn MA from scratch from books, but it is my firm belief that once someone has mastered the basics, understands the Kata, has the right mental attitude, has the right goals, then they can achieve much on their own.
Many Masters in the past trained themselves after a certain point, can one not repeat the past?
To say you cant grow on ones own would unravel the standard the likes of Bruce Lee, Choki Motobu, Mas Oyama and many others build up for themselves.
Give me a man who ardently desires his vision and works on it assiduously and I give you a man with a profound destiny.