The original finding was written by experienced chemists, not physicists. There are some problems where solutions are searched for in the wrong directions.
Our current generation of YCBO-based high-temperature superconductors started out as low-field, low-current, highly strain-sensitive, and over 30+ years of engineering development, these now carry >1000 amps/mm^2 in fields as high as 10T (although these numbers trade off against each other). It’s a matter of time.