As of the most recent figures, VA is currently profitable on a month by month basis, also Alan Joyce stated on the ABC that Qantas are close to break even on the LA route, so it would stand to reason that VA would be break even or better on the same route, given ticket prices are comparable and VA's cost base would be significantly less than Qantas.
There is little doubt that JB won't stick with VA if it continues to make a loss, but there is every indication at present that genuine sustained profit is not too far off, with or without the Delta deal. A tie up with Delta would just put it beyond doubt for the short term.