Why does he bother putting estimated number of years to practice the kungfu when it's all about whether or not you have the inner strength? It just makes people fire deviate and try too hard when they can't handle it.
I guess this is a limitation of having super secret kungfus that only one person is allowed to learn: you dont know jackshit about it. I imagine if everyone practiced QKDNY it'b be pretty obvious sooner rather than later that those with X inner strength can progress, while those with Y cannot.
I'm surprised someone who doesn't care about martial arts superiority such as Guo Jing or Wuji or even Linghu Chong doesn't just photocopy manuscripts of their respective arts and distribute it to the general public to raise the health/skill of the overall population. It'd be pretty beneficial especially in Guo Jing/Wuji/Xiao Feng scenarios where war is always looming.