Vjet if a 777 could burn 4.5t per hour, Boeing would not have made the 787 that carries less and burns around the same . EKs latest 380 (last 7 yrs) bur 12.6t per hour (ULR), have 520 seats (3 class) and carry max ZFW to a bit over 15hrs . The same companies 77W start shedding ZFW at 11hrs, and had to block seats to below 300 when flying dxb to lax . The 77x will do a lot better, but costs half a billion dollars (real dollars that is) a copy . Half of the 300 ordered have been ordered by the same company .
787s cost a fraction of this, are cheaper to operate, so accountants love em .
Rated de is correct when he says QF has a huge cost awaiting to renew the fleet .