I'm having a course on aero engines, and the professor used to be the Principal Engineer of Aeromechanics at GE Aviation. I'll try to translate some of his words to answer some questions:
[Why the westerners stay ahead of the game? Because they set the bars and rules of the game.
Why the westerners set the rules? Because the rules are set by who knows & does the best.]
[Reverse engineering just doesn't work on aero engines, What you can see, measure and duplicate are "Explicit" technology, while the "Implicit" technology set the differences.]
[There's no such major of "Aero Engine" in the US engineering schools.
It's beyond engineering (Technology, Business, Operational & Geopolitics) and it's a multi-disciplinary system.
Aero engines are "The Most Demanding" and "The Least Forgiving". It sets the highest standards of the industry.]
[People are talking about the gap between Chinese and Western aero engines: 40 years? 20 years? or 5 years? Maybe they are all correct. But it's not important, the key issue is when we can catch up with them. In the era of Industry 4.0, China has a great chance to catch up with the westerners in a short time.]
I noticed that many of my classmates are interested in aero engines and want to devote themselves in this career. You may claim China cannot catch up with them, or blame China on hacking, reverse engineering, but we will study, research, and make the changes.