The Taiwan issue is the last piece of unfinished business of the Chinese Revolution of 1949.

China does not need to conquer Taiwan. But to admit Taiwanese independence would be inimical to the idea of China's national resurgence, as well as a stain on the Founders' legacy. Hence the belligerent tone. The CCP has isolated, and will continue to isolate, the island politically, but it does not need to annex it.

Chinese economic influence (covert ownership and overt trade) is likely to make the distinction irrelevant. Taiwan is more likely to become what Hong Kong was until the crackdown (without a treaty-mandated handover): a Chinese economic colony with uncertain political status that provides access to Western capital (and, additionally, technology).