The idea is fun but I think it falls apart when carried very far. For example:

A. Chinese music ought to be utterly unique but often sounds very melodic when played solo.

B. French and Spanish music ought to be more alike.

C. Italian and Romanian music (not to mention French and Spanish) should have more in common with each other than German music.

D. Danish, Norwegian, and Swedish music ought to be much like German music.

And so on.