ETOPS was perused by both Boeing and Scarebus so they could sell big twins to airlines to operate the Atlantic and Pacific more economically, with the comparable safety to the quads they replaced.
Who can forget the A340 demonstrator at various airshows with "FOUR ENGINES FOR LONG HAUL" scrawled along the belt line in 3 metre high letters!!
That didn't last long but, then again, neither did the A340!