The CPC would like the world to believe that nobody can tell it what to do (not least of which for domestic political reasons), but it's not really the case. China may be bigger and more powerful now, but the (media) spotlight on it is consummately brighter.

I'm not terribly optimistic about the developed world's response to a hypothetical Tiananmen 2.0, but I also recognize that predicting what will capture the public imagination is an uncertain business. And in the case of actual worldwide widespread outrage (and accompanying economic penalties), you can look to pre-JCPOA Iran to see how that turns out. Even the US would buckle under that sort of pressure.