For all the interest there is in matters related to Tibet, there is not much music available that was actually recorded in the country itself. The reasons are obvious. After having annexed Tibet, China has not been particularly keen on allowing people to travel around freely in the region. And, as with any other culture from oral tradition inside China, the authorities prefer to have a hand in the way the traditional arts are presented to a wider audience.
Folk music is taught at music schools and conservatories.
Folk musicians from China who perform in the West are mostly professionals, graduated from such institutions - and very probably there is no reason why a student hailing from Beijing can't have a degree as a performer of Tibetan folk music. The traditional music of these people developed directly from the way they conducted their lives. Their world view and the messages they wish to communicate in their songs cannot be treated as separate from the medium through which they are communicated. Moreover, such songs are directly related to Tibetan life prior to the Chinese occupation. In short, Tibetans enjoying their own culture may be regarded by the authorities as highly suspect and subversive.