The incident investigation will surely focus on exactly those things. But: just like shipping aviation is at the mercy of the weather and even though the rules (which are written in plenty of blood) try to anticipate all of the ways in which things go wrong there is a line beyond which you are at risk. I've had one triple go-around in my life and it soured me on flying for a long time afterwards because I have written software to compute the amount of fuel required for a flight and I know how thin the margins are once you fail that third time. I am not going to get ahead of the investigation and speculate but I can think of at least five ways in which this could have happened, and I'm mostly curious about whether the root cause is one of those five or something completely different. Note that until there is weight on the wheels you don't actually know how much fuel remains in the tanks, there always is some uncertainty, to the pilots it may well have looked as if the tanks were already empty while they were still flying the plane. Those people must have been extremely stressed out on that final attempt to land.