Consider for a moment that I am from Singapore and have long time lived there. I do have friends there and I’ve read on our history, but day to day living in Singapore is not my forte. I share with you is a combination of what I know and what I assume.
Cost of living: Singapore is considered part of the “first world” countries. It’s very expensive to live there—one of the most expensive places in the world. Just finding an affordable living space is hard. A “higher” standard of living means it isn’t as easy to just meet, get married, and have a family. At least not unless you are already established and ready to start a family. Many people are afraid that they can’t afford marriage!
Women working: In generations past, women stayed home to raise children while the men supported their families. Now with many, if not most women entering the workforce, they don’t have as much time to devote to raising children as they once had. Some women also choose not to marry, as they can now support themselves.
Demographics: The population is well over seventy percent Chinese, and from what I know of Chinese culture, one spends their twenties working on education and establishing themselves successfully in their careers. Likely the other groups living in Singapore have a similar mindset.
Culture: Marriage isn’t arranged so much anymore. It is done, but the majority of young people are choosing for themselves. This means that they feel they have time and options. They think they can afford to be picky sometimes.
Mostly though, I feel all of these reasons boil down to the curse of the modern world.