The need for young, inexperienced eye candy on long haul flight pales in comparison when you have the senior staff in First/Business Class being attentive to every request, meticulous in detail and making sure you are well rested when reach your destination.
Not to sound like I'm advertising for SQ, but I hated SQ when I was much younger, because despite the good lookers in economy class, they were exactly the same as what most people complain about SQ girls (SPG, boh chup, boh hiew, show blackface etc etc etc.)
After I flew my first business class to Europe did I understand why SQ is and always has been regarded as the best in the world.