EK 777s have 10-abreast making them just as bad as the 787 Y-seat width. Except as I recall the pitch is less than that of Qantas to boot. EY is no better.
SQ is obviously the one to beat for economy comfort and it shows, their product is so good they have shot themselves in the foot because half their fleet is specced with a Premium Economy cabin that they struggle to fill, no one is willing to pay the asking price so what do you do? Discount the seats and give your economy pricing the appearance of being overpriced in comparison?
SQs 787 has 9-across in Y as well by the way. And it will be the aircraft flying punters from Perth in competition with QF.
I did read a rumour that AJ contemplated fitting 8-across in Y, but it was shelved because it would have made the 789 uncompetitive on the other routes it will fly.
Never forget the pax with champagne tastes and champagne budgets are drinking said champagne in the pointy end! Look after them first. 95% of the ones in Y will pick another airline next time unless you are the cheapest option again.