Note https://www.nitrd.gov/pubs/nsa/sta.pdf promising ~100Ghz cryogenic processors by 2010 with sufficient (but seemingly not ridiculous) government investment.
1. the project succeeded and the government has kept cryogenic processors totally dark for a decade with no public leaks or hints to industry (far-fetched, though Skunkworks hid the Blackbird pretty well.)
2. they aggressively funded it as a black project but hit insurmountable design challenges (like quantum computers) or bureaucratic abyss (like the F35.)
3. the funding never materialized.
are any research teams working on superconducting classical computers, rather than quantum computers? does nonlinearity get in the way?
5. The project was funded as a black project without the intention to actually deliver results but rather to justify RSFQ circuits R&D to later use those results elsewhere
I didn't find any of what I was looking for, but I stumbled back onto the fact that Cray II's were cooled by running fluorinert over the components and that the NSA was one of their biggest customers at the time.
Whose to say they aren't still using fluorinert on servers?
But I've also heard rumors about TLAs getting access to pre-production versions of consumer chips (eg, when yields are still sad). And who knows what binning is going on at Intel. If I have a really good production run and I get 95 chips that have absolutely zero flaws, who do I sell them to? When you manufacture something you can't guarantee a certain yield to be above your wildest expectations, so would I even create a product number for the unicorns? Do I bin them with 'the best' chips even though I know they're better than the best?
Or do I just find someone with deep pockets who's happy to take whatever I've got, be it 3 or 300?