Entirely up to the crew to choose the time of landing however I also wonder if they stayed airborne longer to allow the resources necessary to quickly remove the a/c from the runway to get put in place so that the runway remained blocked for the minimum of time. As stated, there were many arrivals/departures they may not have been possible had the a/c landed at the first opportunity after all fixing attempts were exhausted.
^This^. If what is going to happen is what is going to happen, may as well wait until the best time for it to happen. RWY only closed for about an hour. A couple of Jetstars ended up in Brissie, but others didn't have to.