The expat F/O are a leftover from many years ago who have stayed on despite everything. No new ones are required as SIA have a factory in Oz churning out F/O like there was no tomorrow.
Quite soon the 'Generals' will without any discussion get rid of Double crews and Augmented and replace with just F/Os and one Captain,thus saving huge sums of money and no longer make it necessary to employ ex-pat Captains and then with just Locals he can really get to work and screw them into the ground safe in the knowledge that they can do nothing about it, thanks to the draconian labour laws in Singapore, and the hold that they have on Locals to make any dissent impossible.
Once it is 100% Local any moans and groans they have will be of no interest to others I suspect.