Seymour ran refrigerant (fleurinert?) through coldplates on all his designs (and their descendants) up through the Cray-2. I am told that he used to call himself "the best refrigerator repair man in the industry". His downfall came when he abandoned coldplates for the full refrigerant emmersion that gave the Cray-2 its distinctive "aquarium" look. Unfortunately, in later designs he had to run refrigerant across the emmersed boards so fast that it actually caused friction corrosion.

But, yeah, you have a point. Coldplates are old hat in the supercomputing industry. BTW, RISC is too. We used to joke that it stood for "Really Invented by Seymour Cray".