From what i heard from a BA management friend the BA 15 does extremely well for F and J pax and thats what makes it worthwhile-these peopele do not want to change planes in Doha and don't want to fly QR the whole way. So its survived while all the other BA Oz trips have faded into history.
If BA go BoB then I am worried because they have ramped up the charges for things like seat selection alarmingly and seem addicted to trying to screw as much as possible out of pax on extras which i think will come back to bite them.
And as for short haul not being profitable, as pointed out thats just an accounting scam. All those AB 320 series whizzing around pretty full every day must ratchet up a lot of revenue even discounting interline stuff and without the costs of crew accomodation on long haul and massive amounts on fuel they have to be a very nice little earner.