I keep hearing about "the promise" and "achieving quantum supremacy" (again!), but is there a real example of a quantum machine doing something useful in real life?
On the other hand you have
The "factorization" done with quantum computers involved cherry picking special numbers so that a special "compiled" circuit (knowledge of the answer is required in order to do this) can be used instead of the full thing. That makes the semantics of the executed program "slightly" different.
What the claims say: factor(a,b)
What the implementation does: println("3").
Simulations of condensed matter simulations performed on QCs (google's OTOCs, quantinuum's HUbbard model) are not easily accessible by the regular computer. There are people working hard on simulating these results classically so it's quite likely they'll be simulated eventually. We're at point where classical computers are still in the race thanks to immense scale and algorithmic progress, but I think it won't be the case soon.
> something useful in real life?
usefulness is subjective. There are results that are potentially interesting to some people on Earth (as opposed to RCS).