According to ASML, EUV requires an incredible amount of institutional knowledge to pull off, including for the optics involved. And they're not worried about a machine being taken to an unauthorized location because EUV machines are huge and assembled on-site for customers ("bolted to the ground") by ASML itself.

Given the pace of chipmaking die shrink, I wouldn't be surprised if they can retard the ability of China to get up to speed on 7nm before the next lithographic generation becomes common.