I don't think high vacuum is the main problem. I used to work closely with people who did serious high vacuum heavy lifting (with RHIC at Brookhaven) and they always gave off the impression that it's plenty difficult, but it's engineering-project difficult, not research-project difficult. There are solutions, they are understood, and they work at scale. Though they might not be pretty.

No, I'm guessing it's something else. I can't imagine complexity is the issue, given the nightmare that is the ASML scanner, so I can only guess that some property of the light generated by synchrotrons is troublesome and not easily correctable.

If that's not the case... perhaps there really might be a business opportunity here?