DA revolvers, ESPECIALLY the old style action Colt revolvers are considerably more complicated with many more parts than a Single Action.
They required a lot more hand fitting and adjusting then any SAA.
The days when any major gun company can spend the time and effort to build a low selling Ferrari level revolver are over.
I don't know about now that Colt reintroduced the New Frontier, but a few months ago Brent at Colt told us that ONE MAN in the Custom Shop was building ALL of the SAA revolvers.
Colt has been discussing bringing a DA revolver back sometime in the future, and my belief is that when they do, it'll probably be a Magnum Carry small frame type DA revolver.