I would also agree with your assesment but Bruce though he was a
prodigy of sorts really did not invent anything new rather he
combined things that work and with his physical talent performed
them better than those who also had the media exposure. As for
age, it is really a matter of the individual but the question here
is that unfortunately there are those who in America and around the
world who have little training, maybe one decade of traditional
training and have not garnered the "experience" to have the wisdom
or understanding to develop or create a "new" style consequently
claiming the rank of 10th Dan or "Soke". More so it is from the
traditional standpoint disrespectful to your teachers and the art
to "claim" a title or rank rather one is respected by their peers
and students as one who has acquired great skills and honored by
being the recipeant rather than the claimant of such "titles"
and "Rank". It is like the old saying goes...."you earn it!" This
age of 50 is a designation that is a "suggested standard" in Japan
but understand that even in Japan rules are made to be broken. One
must display exceptional skill and knowledge and have given their
life "honestly" and "morally" to their chosen art to net the "given"
title or rank. i.e. Kuniba,Shogyo of Shito-Ryu who at the age of I
believe 32 was "given" the rank of 8th Dan(unusual in Japan)in
Karate-do. He had trained since birth under his father a "meijin" in
his own right and then also trained under several other "meijin" as
required by his father before he was to assume the leadership of the
system. This is legitamate. Most unfortunately are not. Remember
Bruce Lee was accepted by his peers and students as a "master". He
did not boast himself as one, only that he had a clear and different
understanding of the art he studied. By the way he also since early
childhood was a student of his father in Tai Chi Chuan and later
under the toolage of Yip Man in Wing Chun, these all being
legitimate years of training. I hope this helps with the
understanding that 50 yrs of age is a standard rule of thumb but as
in anything there are exceptions to the rule. This my friends is
only my view......have a great day! Humbly just a student.