Why dont we all just accept that this has nothing to do with safety and everything to do with politics.
The regulator of one country which now builds mainly twins (777, 787) wanting to make it difficult for the quads (340 series and 380) built by another group of countries. If you make quads obay the same rules as twins after an engine failure then some of the economic advantages of them disappears. And in the same breath if you can allow twins to do unlimited ETOPS then you take away another advantage of quads.