They are opening up, because they now [suddenly in some cases] have so many cases themselves (S. Korea is at ~300'000/day), it seems futile to still require quarantine. New Zealand did the same thing.
China hasn't got many cases, so they won't open up, IMO. In fact, the more the gap is between other countries count, and China's, the more likely they'll increase quarantine.
Of course.....this will all change if/when the cases start skyrocketing in China also....