I don't think it's "even more reasons" at all. VS was an irrelevance in the UK-Australia market faced with the competition, especially the Gulf competition. How many successful ultra-long-range routes can you point to around the world? Is there really a demand to be squeezed into an economy seat for 20+ hours rather than stopping and stretching your legs in the middle? Plus the advantage of a hub midway is that the hub airline can use larger aircraft with lower seat costs, so can price more aggressively.
Singapore's ULR ops direct to the USA are probably instructive on how desirable pax find that type of service. Now canned, I get the impression it never really took off as they would have liked (pardon the pun!).
Not just stopping and stretching legs, the option of a stopover also exists, thus breaking up a very long journey. Many travellers on Europe-Australasia take advantage of these.
ULH may have attractions for F or J pax, or those in a desperate hurry, but hell for those in Y. Not surprised that SQ's got canned!