Simple Maths
B A L,
Shame QF do not only fly SYD-MEL because you are right they would be making a killing!
Just do you maths on a SYD-PER or BNE-PER sector!
These surcharges (domestically) work in favour of the carrier on short sectors I am sure CBR-SYD looks even better than SYD-MEL.
I hope you, or the poster on crikey have not wasted money on an economics degree. If you have seek a refund!
I am not in favour of the surcharge as QF (and others) add it quickly, but I do not think they will ever remove it!