They pulled out because they were not making money on them and people were more lured by the cheaper fares by JQ and DJ.
They certainly haven't ruled it out and I can see a return - they need really to have services to SYD MEL and maybe even PER to make it viable. Just operating from one city only wouldn't work. And they would need a couple of services per day from each destination too.
But the bigger question is how profitable is the OOL route for JQ on its own and can they afford to put a dent in it to help QF? They should be able too.