From my layman's understanding, parts of Hong Kong had to be returned to China according to the terms of a 99-year lease; the rest of it was dependent on the le

From my layman's understanding, parts of Hong Kong had to be returned to China according to the terms of a 99-year lease; the rest of it was dependent on the leased territory for stuff like fresh water, so it didn't make sense to hold on to it. Also, there was fear that China would take it by force. With Taiwan there's no such legal obligation (in fact some even consider Taiwan the legal government of China). It also has an industry of strategic importance (semiconductors) and is much easier to defend: (again, not an expert) I've read opinions that it may not be even possible to invade due to the prohibiting coastal terrain.