Basically, exactly as Wizofoz says. Emirates offers CONNECTIONS, QF would need to fly into Dubai from SYD/MEL/PER/BNE and then tie up connecting flights with other airlines or operate those flights themselves.
They would have the problems of coordinating timetables, code shares, baggage transfers and revenue sharing just to start with.
Emirates can offer Birmingham UK to Perth with one stop via Dubai. QF would only attract passengers going to Australia where as EK can offer them Africa, Far East, Asia and South America, possibly North America if the price made up for the extra travel time. A seamless, easy way to travel with all the ease of staying on one carrier.
With modern aircraft it is possible to fly from Dubai to any point in the world non stop. With its central location it covers a huge chunk of the travel market.
QF don't have the aircraft or product to compete. B744s are too big for frequency on the thinner routes, and who wants to fly long range on a B767 ? EK enjoy considerable cost savings with Dubai based non unionized labour, and don't have to follow Australian workplace laws.ie they don't have to pay inflated wages to non performing personnel who can't be sacked.
Had QF bought B777s and operated a hub through Singapore it could have had a much more extensive European network and competed on the major city routes to Australia. EK now have a huge lead which will be difficult to catch even with the B787.