They can't find an airplane that can do it profitably. Also, "Goh didn’t identify the U.S. cities for direct flights by Singapore Air in future."

SQ has trouble getting more fifth-freedom rights, because the way I see it what can they give away to get more? It sounds like they've asked but haven't been able to get other countries to budge on giving them more stopovers with full traffic rights. The non-SIN hub in India might work.

One answer he gave was to partner up with VA and NZ, not sure how that would work for flights to the U.S. though.

Whatever tech advances happen, SIN will always be a poorer hub for connections to the U.S. when you have the likes of HKG, ICN, and NRT/HND.