To me, the theory is as much a communication tool as a knowledge. It is a common language for musicians to communicate musical ideas, at a higher level than musical notation. E.g. I can go to a jazz open mic, someone says the progression is "ii V I in Dminor", or a blues jam and its "I IV V, A major", or a Grateful Dead-type jam and its all mixolydian in B, and everyone is on the same page out of the gate. The theory is you know all of the scale modes, AND what they are called, AND can tell another musician what you're doing and why. Tons of people can play interesting things outside of the box, without know why or how it's defined.

I can get behind this definition. But even following that definition, people without theory knowledge who know how to play would know a third of theory if you split the three categories that you said equally. I venture to say that the concepts themselves weigh more than an even third though.