[btgeekboy]

Having 2 engines go out is such a rarity that it almost never happens. And when it does, it’s usually due to something that would have affected 3 or 4 as well.

ETOPS regulations also ensure (at least for the US) that if one engine does go out somewhere over the ocean, you’ll at least get to land somewhere.

[fyfy18]

For anyone wondering the longest ETOPS diversion was for a 777 which flew (and landed without incident) for 192 minutes on a single engine.

http://www.airliners.net/forum/viewtopic.php?t=191343

[seanmcdirmid]

The end of the Cold War made direct two engine flights viable because (a) we could fly over Russia and (b) Russia was nice enough to open up a bunch of airports in the Far East (with money from western airlines) to comply with regulations.