Personally never paid too much attention to this Hong Kong other than a couple of weekends a couple of months ago. Just a very stalemated situation on the ground.Just two thoughts on why the CCP will not do anything.
1. The Hong Kong civic elections are coming November 24, so to move troops in before that date serves no purpose because with or without Chinese troops in the streets, those elections will happen regardless. That is a fact of Hong Kong life, that once in a while there is an election where hardly anyone comes to vote. Will it be different this time? Hard to say to be honest.
2. It is the competing systems. Right now, there are a few protest movements is a couple of democratic countires and much political disruption in anglo countries like America and the U.K.
What is happening in western countries it is freedom and democracy or just plain nihilism. Like what the anarchists believe in, which is nihilism. Does the system always leads to nihilism, ie disenchantment with the system? What is what got Trump elected.
This is the "Chinese dream" versus "western nihilism".
Right now, I really doubt the PRC will do anything for Hong Kong. In the long run they will incorporate Hong Kong into Guangdong province. At the moment the Chinese dream will beat up on western nihilism in Hong Kong.
There is anarchy in the streets and nihilism in people's hearts, some people at least.
Let it burn indefinitely could be the PRC strategy for Hong Kong at this point.