I'm not an expert at all so I have to wonder which core technologies were/are too expensive to duplicate for China? Afaik semiconductors represent the cutting edge of manufacturing technology; if China is able to duplicate (or even innovate, as demonstrated by "3d Logic folding") in this industry, I can't imagine how any other sectors would be too expensive to duplicate.

Who knows how far they progressed in lithography once it became clear that withholding technology would be the official state policy-- I heard the Chinese state got involved in developing EUV in a way comparable to the Manhattan project in scale and secrecy.

I worked in China for 9 years and I really don’t think it makes much of a difference. China is not dumb enough to think that just because they can get it from the west today they can get it from them tomorrow. They were always going to develop their own semiconductor and jet turbine tech and industries, among other. They didn’t do it just to spite the west for not selling them the chips they wanted.

Withholding technology is the only tool we have. If we let them have the tech it's not like they'll start depending on us. They will simply replicate the machinery and then someone else will be writing a comment on Nacker Hews in this alternative Earth about how we were such fools in the West to simply let them have our technology thinking that would make them depend on us. In fact, we have this evidence because all the news about Hygon Dhyana being based on a nerfed Zen 1 had all Internet commentary shaped like "We're such idiots to let them have this. We are the eternal morons!"

Literally every non-embargoed technology they have access to they instantly build and enhance. They have industrial and manufacturing iteration ability far beyond what we have. They won't be grateful to us, they won't be dependent on us, they won't be supplicants. They are well on the trajectory to being an equivalent world power with divergent objectives and thinking that handing them R&D is going to slow a negative outcome for us is wishful thinking.

Sometimes the only plan available is not a great plan. That's just how it is. The world sometimes gives you constraints that don't have a happy solution. You race down the precipice on whatever you have. And look what we earned for it: almost a full decade before they got here. That's amazing.

The US only had the bomb exclusively for 4 years before the USSR got that. We had 18 months before they got nuclear submarines with ballistic missiles. We got 8 years of EUV that China couldn't match us in. Precious 8 years and ongoing.