As with most places in the world there are expat pilots for one reason only...
Not enough locals for the job.
It’s probably going to get worse as it becomes a less glamorous job or people don’t have money to pay for the cadetship.
On that is it really a cadetship if paying? SQ still does the proper cadetship yes?
Singapore no more expensive than many world cities, can cost a **** load or be reasonable. All depends on lifestyle, oh unless you have kids!