When will it happen ?
Just wondering if one engined airplane will burn less fuel than a twin.
Okay, when you lose one engine you lose all power. But there must be means to minimize the CONSEQUENCES of powerless landing/ditching. You can reduce the cinetic energy by lowering the falling/gliding speed with parachute or dragchute.
Airplane designers can put engine intake where the risk of bird strike or ingestion is nill or limited.