There are basically three reasons for non-Chinese people not prioritizing Chinese localization:
- On the technical level, the Chinese writing system is difficult to deal with because of the sheer number of different characters. It’s easy to find or make a small pixel font that supports the Latin alphabet, and not much harder to support Cyrillic, but Chinese fonts require huge numbers of characters, and the characters need to be relatively big to stay readable.
- On the legal level, it’s easy for an outsider to accidentally violate Chinese censorship laws, which can result in the game being blocked in China.
- On the economic level, the Chinese market is notoriously difficult to break into for outsiders. There are some major exceptions to this, but that’s all they are, exceptions. This affects even free indie games: why bother translating into Chinese if very few Chinese people are interested in the game?