But the US banned ASML from selling to China so you need to catch up with ASML and Intel/TSMC at the same time. Now, I don't know when ASML started researching EUV but they were certainly working on it in 1998 -- which doesn't mean it'll take twenty years to replicate it because surely some of it is public but still, it's a big, big project. https://go.gale.com/ps/i.do?id=GALE%7CA56970339&sid=googleSc...
do you know what the cost breakdown is when building fabs?
The channel's older videos have a lot lot of information about fab economics, though I dunno if there's one that has a general cost breakdown.
So I think the cost is largely that every part must be engineered to perfection.
e.g. watch this about the light source, its completely bonkers https://www.youtube.com/watch?v=5Ge2RcvDlgw
Source: my company is one of those not allowed to sell this type of software to China
Although we could mention the B-29 which actually cost 50% more than the entire Manhattan Project -- or, to be closer to present day, the F-35.