The 787 may be almost a 772, but who is ordering them these days anyway? They are old technology
The 773ER is where it's at and I doubt any 787 will ever get close to it's economics. Especially if they re-wing it and modernize it further.
I bet Qantas do something stupid, rather than ordering the 777, they will go for the A351's. That's what you get from the finest airline management in the world.