This crew did not have that, and that would have been obvious to them for a long time.
Not necessarily so. On long haul flights, any 'extra' fuel taken on in anticipation of the 20 minute holding at destination can easily be used up if you do not get the optimum levels or the winds are incorrectly forecast or you have to do a lot of unexpected vectoring around weather that wasn't forecast.
Most of the time you get near enough to the levels that you want and as long as the forecast winds are reasonably accurate you will not have a problem. However, there are occasions when everything conspires against you and it will not be until fairly late into the flight that you will have a clear idea whether your fuel situation will be critical.
If the reported incident had been a regular occurrence, I could have understood the criticisms being bandied about by a few posters on here. However, considering that this was an isolated incident, I think that some of the comments based on 20/20 hindsight are a little off the mark.
By all means, the discussion surrounding the technicalities of calculating fuel loads based on historical data and ways of promulgating expected delays much earlier to the crews is good. It is not very appropriate to compare the differences between a short haul flight and a long haul flight when it comes to any of the numerous vagaries that can take their toll on fuel burn over 8 or more hours.