In my younger days, in my ignorance, I used to think the same, but after studying and understanding Chinese philosophy and thought process, it makes absolute sense why they aren't trigger-happy. The Chinese have no problem waiting it out and allowing the U.S. to burn its goodwill and treasury; they play the long game while building their own capacity.
Remember, in the 1990s, when the PLAN was smaller, the military used civilian gray cargo ships, often welding howitzers and tanks onto them as improvised fire support platforms for landing forces. Today, it's grown leaps and bounds, and it has invested in its manpower and industrial base. While it has caught up to the United States in terms of technology, it still has ways to go.
The Chinese, first and foremost, look to maintain internal harmony amid external chaos. It knows eventually it will have to fight, and it will, but only when it's guaranteed a victory.
In Chinese calculus, they remove emotions and make decisions based on sound, calculated logic. The Muslims would have done well to practice this.