Then why hasn't COMAC produced a viable jetliner?
The US for example trying to get back some of its domestic manufacturing prowess, after decades which has outsourced it to China which has gotten really good at it, has a 10-20 year barrier to overcome before it can even start to get to the same level, and that's if all goes well and no stupid decisions are made. Which is not very likely.
You sure? C919 didn't start commercial flights until this year (2023)
Economic and industrial espionage has a long history. Father Francois Xavier d'Entrecolles, who visited Jingdezhen, China in 1712 and later used this visit to reveal the manufacturing methods of Chinese porcelain to Europe, is sometimes considered to have conducted an early case of industrial espionage.[16]
Historical accounts have been written of industrial espionage between Britain and France.[17] Attributed to Britain's emergence as an "industrial creditor", the second decade of the 18th century saw the emergence of a large-scale state-sponsored effort to surreptitiously take British industrial technology to France.[17] Witnesses confirmed both the inveigling of tradespersons abroad and the placing of apprentices in England.[18] Protests by those such as ironworkers in Sheffield and steelworkers in Newcastle,[clarification needed] about skilled industrial workers being enticed abroad, led to the first English legislation aimed at preventing this method of economic and industrial espionage.[19][18] This did not prevent Samuel Slater from bringing British textile technology to the United States in 1789. In order to catch up with technological advances of European powers, the US government in the eighteenth and nineteenth centuries actively encouraged intellectual piracy.
I can't justify slavery in x country because "well the west did it before and so now it's their turn" (to use an extreme example and yes I know that slavery has already occurred in almost every country/is still occurring in some).