I don't underrate the historical significance nor the challenging logistics of the operation, but I do think the extent of Australia's participation in it needs to be kept in perspective: there were about 3000 Australians involved.
The context, as Wikipedia tells us, is that 160,000 troops crossed the English Channel on D-Day, with 875,000 men disembarking by the end of June and presumably there were many more involved with the air and naval support (I see that most of the Australians were in these areas).
I do find it interesting how particular historical events are commemorated, and others are hardly mentioned. Perhaps it's understandable that we don't hear much about one of the great turning points in the war, the Battle of Stalingrad, but there are probably other events that also remain in the background (the Battle of El Alamein comes to mind). Presumably, an element of selectivity is inevitable when thinking about historical matters, but it is interesting to reflect on how the "selection" process operates.