Like many others pointed out, Korean dramas tend to be more popular, also shorter so it's fast to translate. Also, like someone pointed out: translating is not an easy job.
I was a translator once, not for dramas but for japanese mangas, and let me say it's a repetitive and sometimes underrated job. Keep in mind that fansubs translate everything for free, and if translating something written is already hard, imagine how harder it's to watch and rewatch one scene only to translate it into something foreigns would understand?
That's why the demand is important: if people watch and ask for more, then it's obvious that the translators will do it. Chinese dramas are unfortunate because they have a number of episodes far superior (most of times) and, it's only expeculation, some watchers simply don't want to watch 30 episodes or more (if you compare to kdramas or jdramas, that's a lot of stuff, mainly for the ones used to shorter dramas)
But I understand the struggle. I'm a fan of chinese dramas, and there are plenty I really wanted to watch but can't because there's no sub.