On Guard, QF's loads are reasonable but only because they have been reducing the number of services. At the peak (18 months ago) they were operating 6 services per day across the Pacific to LAX - now they are probably averaging 4 services per day. This has kept the load factors reasonable but I doubt that they are making money on the route because they would have sold the tickets at a discount to be competitive with V Oz and the impending competition from Delta. The biggest hit for QF (as well as SQ, CX etc) is the large reduction in premium traffic.
In very competitive situations like this, it is normally the weakest of the incumbent airlines who suffers the most, so, I wouldn't be surprised to see United withdraw from the route soon.