Despite that, I still don't think the art itself is incomplete. Teachers can only convey a fraction of their knowledge. Hopefully, this will contain the basic foundational elements on which the art is based - philosophically, strategically and tactically.
I still believe it is up to the person to make it their art, and to attain the highest level that the art can offer. That's why it's called "art". Skill and mastery of one's craft is art.
I can see why you think it is incomplete from some perspective, but I would say that it is your knowledge that is incomplete. And yes, perhaps sometimes you need to go outside your art, and experience a different training paradigm in order to see what you are missing in your training. Rather than what is missing from the art.
I remember asking my teacher once, about something that was seemingly "missing" from our practice, and his response was "well, obviously... one must adapt to suit the situation"....
Still, it didn't take me 25 years to work out I needed to move on