How would that even work with inference where the expected output will be different between 3 runs with the same input?

They are not using 6nm process chips in the ISS. The computers themselves were made before that process existed. An off-the-shelf space hardened computer system uses 65nm process. Cosmic rays is a very general term, it covers basically everything that flies around in space, that includes sources like the sun, which is hammering everything in the solar system with rays. Outside of the atomsphere there are so many more cosmic rays that non-space hardened computers can not even make calculations. Combined with the difference between the bit flip rate when you make transistors 10 x smaller is also fucked up high. One CPU cycle will have enough erros to make the computer useless. It's a multi-faceted problem and when the largest limiting factor is weight & size, it can't be solved with scaling.