In the 1980s, many musicians and journalists in the English-speaking world began to draw attention to music from around the globe--such as mbaqanga from South Africa and quan hg from Vietnam--that can't be easily categorized according to British or North American popular music genres, typically referring to such music as "world music." While some scholars have welcomed this development for bringing diverse musical forms to prominence in countries where they'd previously been overlooked, musicologist Su Zheng claims that the concept of world music homogenizes highly distinct traditions by reducing them all to a single category.

Which finding about mbaqanga and quan hg, if true, would most directly support Zheng's claim?