another reason why China can't build jet engines: the jet engine manufacturers never relocated their manufacturing to China, which therefore prevented the Chinese from getting their hands on their IP.

it's well known that the way China dominated in solar panels was by "transferring" (aka stealing) the IP from US solar panel makers who had foolishly set up shop in China to reduce costs, and ended up going out of business once Chinese companies got the IP and was able to use their resources or gov subsidies to undercut on price.

I'm not saying that this is always been the reason for China's ability to quickly catch up but it is definitely a factor. Anyone who has worked in China (as I did for a number of years) knows that IP is not safe there (it's not just foreign companies who experience this, Chinese companies find their IP copied by other Chinese companies), and the courts provide almost no help to foreign companies (this may have changed as of 2017, when I left China, up until that point no foreign company had won a significant court case against a Chinese company in a Chinese court).