Why should be buy American stuff when Chinese products are as good, HQ-9P
Yeah...Tell that to the Iraqis post Desert Storm.
Here is the real world deal...
Suppose you design a new compound for tire (or tyre). What is the ultimate test for that compound? Not in the lab. The roads and the environments determines if your product is good enough. Same for a new airfoil, metallic composite, plastics, and so on. Concrete must withstand constant compression, and unpredictable exposure to water and heat. Seemingly, we modern people still have a hard time replicating Roman Empire era concrete formulation. In other words, the ultimate test for anything is
WHEN, not if, that thing goes up against an opponent that tries their best to destroy that thing. Nowhere is that more 'real world' than war and weapons, and military history is repleted with failures of hardware, software (theories), and people, when each of them clashed. The Maginot fortifications were great ideas of software and hardware, until tested.
Look at the admonition to go after the Archer and not his arrows. Modern warfare made that increasingly difficult. The Archer is separated from the battlefront by distances literally beyond view. You have no choice but to deal with his arrows. You must develop two separate branches of arms in software (theories and doctrines) and hardware (aircraft and missile interceptor). Each to complement the other but at the same time, operate independently when necessary. You go after the Archer in offense while shooting at his arrows in defense. One can fail while the other succeed. Or if you are good enough, both succeed.
Back in Desert Storm, Soviet and Chinese weapons systems and war doctrines failed spectacularly. There was a 'clash of civilization', in a manner of perspective, and the Soviet-China versions lost badly. US airpower had many failures in hunting the Archer, and many failures in dealing with his arrows. But the one good thing about winning a war is that whatever that you failed during the war, in the peace you have the opportunity to find out where and how you failed. Losers seldom have that opportunity. Chinese products of war, especially on the technological front, as just as good? Get into a war and find out.