Progress continues. Silicon carbide electronics is coming along nicely outside of NASA. There's now a small system on a chip, from a company in Arkansas, rated for 500°C.[1] There's interest in high-temperature ICs for sensors inside jet engines and down-hole sensors for oil drilling. Silicon carbide power transistors that can run very hot without damage are commercial products.

I wonder how you assemble circuits of components that run above solder-melting temperatures. Laser welding, probably.

[1] https://www.ozarkic.com/products/