Tim Clark is on record as having said he would like to see a 'round the world' 380 service.
Ek have recently announced that they will operate the 380 to KDFW this year. Even if QF had the initiative to take the 380 from SYD to DFW they don't have the aircraft.
Maybe by freeing a 380 from LHR they could go to DFW twice a week .
Sir Tim would probably like that.