We've already passed the point where superconductors need liquid helium: https://en.wikipedia.org/wiki/ARC_fusion_reactor https://en.wikipedia.org/wiki/ARC_fus

We've already passed the point where superconductors need liquid helium: https://en.wikipedia.org/wiki/ARC_fusion_reactor https://en.wikipedia.org/wiki/ARC_fusion_reactor "The most probable candidate material is yttrium barium copper oxide, with a design temperature of 20 K, allowing various coolants (e.g. liquid hydrogen, liquid neon, or helium gas) instead of the much more complicated liquid helium refrigeration chosen by ITER."