The profit margins have got to be a lot higher on those little things than they are on a tuned SAA. They may have run into the same issue Colt did with their double actions - not enough demand/volume to cover manufacturing expenses.
Has nothing to do with it. USFA was 12-18mos behind on revolver orders. Sales were not a problem. They are doing the Zip gun because that's what their flaky president wants to do, nothing more.