[analog31]

An interesting analogy that comes to mind is the electronic technologies that have tried to supplant silicon. I remember, perhaps as long as 40 years ago, reading that gallium arsenide could make faster transistors than silicon, and that we would soon have GaAs computers. Similar for other things like optical computing.

But every time GaAs cleared another hurdle, silicon also moved forward, kind of like the tortoise and the hare. There are certainly uses for GaAs, such as microwave amplifiers, but no GaAs computers yet that I'm aware of.

[IvyMike]

The Cray-3 was GaAs, and apparently Cray shipped one of them.

https://en.wikipedia.org/wiki/Cray-3

[ThrowawayTestr]

Gallium nitride transistors used in compact power transformers.

[Dylan16807]

On the other hand we're looking at near-linear differences in speed with GaA, and it's easy to measure a pretty precise difference.

It's hard to even demonstrate how quantum annealing scales at all.

[pinewurst]

Or cryotrons or Josephson Junctions vs ultimately CMOS