1) It has yet to fly
2) It will break when it does. All Aircraft do in development.
3) They have NO experience operating stealth aircraft, let alone operating them in combat. The learning curve is steep. VERY steep. Even we can't keep our stealth planes at 80% combat readiness, and we've been doing this since the 80's.
4) All they have is a prototype. And a future hangar queen. They have none of the logistical support systems in place to turn this into an effective combat aircraft. We already have countermeasures in place. Stealth aircraft are not invisible to LADAR. Everyone needs to unclench.
You ignore one fact. The Chinese try and keep on trying. The West has scaled back almost EVERY major defence programme since the Cold War. The F-22, Eurofighter, Seawolf class, Zumwalt class DDG (from 30 ships to 3) and several more. Even the F-35 is not safe.