This effect is reduced by the fact that there are multiple romanization systems in use.
Even taking that into account, the diversity is quite low. There are a lot of Chinese characters, but very few of them are actually used as surnames. Less than ~500 names are shared by more than 95% of the population, and most current surveys arrive at way less than 10000 in active use. There are two- and three-character names, but because of their low occurrence they are even more vulnerable to various processes that reduce the diversity of family names.
Chinese family names carry great significance. They were often assigned as rewards, and people adopted different ones for various reasons. This makes their distribution and future development subject to more than random chance.
Even taking that into account, the diversity is quite low. There are a lot of Chinese characters, but very few of them are actually used as surnames. Less than ~500 names are shared by more than 95% of the population, and most current surveys arrive at way less than 10000 in active use. There are two- and three-character names, but because of their low occurrence they are even more vulnerable to various processes that reduce the diversity of family names.
Chinese family names carry great significance. They were often assigned as rewards, and people adopted different ones for various reasons. This makes their distribution and future development subject to more than random chance.