I don't know why QF says they can't operate to Europe profitably. SQ operates:
SIN-NRT-LAX A380
SIN-FRA-JFK 744 soon to be A380
SIN-DME-IAH 77W
SIN-ICN-SFO 77W
SIN-HKG-SFO 77W
SIN-BCN-GRU 77W (oh and they're making a killing on this. Flights BCN-GRU overbooked for weeks)
SIN-EWR vv A345
SIN-LAX vv A345
The geographical challenge SQ faces in operating from Singapore to the USA and Brazil is the same challenge which QF faces operating Australia-Europe. Thankfully though, SQ didn't just withdraw from the USA and opt to put its pax across the pacific or atlantic on codeshare partners.
MOst of the routes have been operating for decades, and many like SIN-DME-IAH and SIN-BCN-GRU are very out of the way, circuitous routes.
If a Singaporean carrier can fill flights between Spain and Brazil, two countries which Singapore has little cultural or economic ties to, why can't QF fly more than twice a day to London ?! Anecdotal evidence suggests that SQ's BCN-GRU is entirely filled with Spanish and Portuguese speakers, and the meal service is a massive pointing exercise between pax and crew!
Obviously SQ only manages to do it because they employ slave labour from Thailand on a base wage of $250 a month. Oh wait, that's not SQ is it?