It should surprise no one that President Xi took a hard line against the Hong Kong #protests even after Carrie Lam's acquiescence and withdrawal of the extradition bill. Xi rules #China as the most personally powerful leader since Mao himself--autocracy does not tolerate any sort of challenge.
Xi's strong rhetoric on Hong Kong is predictable, but it changes nothing. Hong Kong is still China's main artery for foreign investment and international commerce. Hong Kong's liberalized laws and politics are a main reason why. A crackdown would shatter those civic structures, and that would likely end Hong Kong's role as a major Asian commercial center. There is no way that does not damage China's #economy in significant and potentially permanent ways.
The conventional wisdom holds that Xi will "get tough" on Hong Kong. But that does not mean Xi holds the high cards. He can only destroy Hong Kong's economy. He cannot unilaterally replace it, nor can he easily do without it.
Xi may yet send troops into Hong Kong. It will likely be a mistake when he does.