SQs A340 had a large number of possible routes on the SIN - JFK route, depending on the winds. I heard that 1 ton of fuel loaded in Singapore was worth 250kg at the end of the route due to the burn off just carrying it. Obviously the B787 will be much more efficient but I can't help feeling that prestige and publicity are playing a part in the decision.
Time will tell, and I wouldn't be surprised to see the route changed to via Singapore instead of nonstop which would allow Singapore to become a mini hub for those who don't want to go through Dubai.
Once they can crack London - Sydney non stop without packing economy class passengers in like sardines, the money will be pouring in.