Unless SIA are prepared to pay for Customs attendance then it will probably go the same way as the others.
With all the politicians and civil servants spending taxpayers money rather than their own and all the business men on expense accounts I would think they would have a very lucrative market.
A one stop connection to the rest of the world on a premium airline which bypasses Sydney would be welcomed. Also Singapore - Wellington could be a useful connection for cities not served by ANZ.