[microgpt]

Materials other than silicon would be an interesting idea, but I doubt even SpaceX is that crazy.

Not only does cooling increase with 4th power of temperature as you said, but power is abundant, so it may actually be practical to use more power to run chips of a different material at a higher temperature. That's a great idea, if it can actually be pulled off.

There's nothing inherent about electronics that makes it stop working around 120 degrees - that's just the practical limit of silicon. Other materials can withstand higher temps but may not be as practical in other respects like bandgaps.