[rickyrick]

There could easily be a true wrist brace that allows for one handed shooting of the AR pistol.
However, it would not look very cool. I imagine something that looks like forearm crutches.

As an avid AR pistol owner I can say without bias that the current braces are designed to have the silhouette and appearance of a stock.

You don’t need a brace or to shoulder an AR pistol to shoot it accurately.

I also contend that many revolvers cannot be fired one handed easily.