The key advance is the understanding that, at high temperatures, tiny irregularities in a steel's structure can disrupt its internal magnetic fields, making the rigid metal soft.
"Steels melt at about 1,150C (2,102F), but lose strength at much lower temperatures," explained Dr Sergei Dudarev, principal scientist at the United Kingdom Atomic Energy Authority (UKAEA).
Engineering is the art of making what you want from what you can get at a profit.
I recall several years ago a note about single crystal metals being studied for jet engine turbines, a decidedly high temperature application. Crystal grain boundaries are implicated in metal creep and loss of strength. Nano crystaline and amorphous metals are other interesting directions for advanced materials. I don't know how they would react to elevated temperatures.