I watched the video recommended by awalton, and it's definitely as insane as he says it is. I can't believe a synchrotron would be that much more expensive, considering that a single storage ring can have an arbitrary number of output ports.

The main issue with using a synchrotron or Free Electron Laser EUV source might not be so much about the technology, but more about the mindset of the clients (Samsung, TSMC, Global Foundries, Intel). Up until now lithography has been something they would buy as a "box" which would be shipped to their fab, "plugged in" and commissioned.

A Free Electron Laser EUV source would be a facility on it's own, similar in size to a small powerplant built adjacent to your fab, and multiplexed to a dozen or so EUV wafer scanners, that's quite a different endeavor.

And after that, and few EUV multiple patterning litho generation, lies a pitch black abyss called Deep X-Ray Lithography, the only thing that can push things closer to 1nm