If it's possible that the polycrystalline structure is what determines superconductivity, and so this is a purity issue?
Could we perhaps find suitable alternative combinations of elements that are more inclined to form these ordered polycrystalline arrangements (superlattice)?
For example finding alloys that have atom A that attracts to atom B more than it attracts to atom A, and atom B that attracts to atom A more than it attracts to atom B, where these particular elements are also good candidates for materials that are likely to exhibit superconductivity, and are heavy elements so they're likely to more stable at room-temperature, so they have higher Tc?
Or is this a dead-end way of trying to find a room temp superconductor?
Or perhaps they thought it was an entertaining response and don't actually believe in the fear narrative.