I don't know about that. If you DO know how to play a musical instrument, doesn't mean that you excel at it, or what comes out of that instrument in your hands is melodious, brilliant, etc. I think that basically creating good music requires these things: creativity, patience, ability to add something special or unique, and THE EAR. I think hearing is highly underrated in judging talent, especially talent in creating music. If you don't have the ear to hear how certain notes go together, how they interact and create the desired effect (i.e., trance is designed to hypnotize, and I don't mean under the influence of drugs, which unfortunately that is what it's used for sometimes, but I don't, and I get goosebumps listening to the hardcore beat), then it's for nothing.
And some of the best musicians never took a drop of music theory (I believe Jimmy Hendrix was one of those, didn't even know how to read music - used colors instead).