The snowboarders were so close to getting home alive. They were less than two kilometres from the top of the Crackenback chairlift where there was food and shelter. Thousands of cross-country skiers have gone past the place where they perished. Many have camped there.
It may be early to speculate but a fairly common pattern with these sort of events is that the snowboarders, skiers, hikers, divers or whatever do not recognise the danger they are in until it is too late.