Hahaha! This is a funny question. Despite all politically correct (or even heartfelt/earnest) statements to the contrary, class will *always* exist in societies- even communist ones where everyone is theoretically equal.

Singapore is no exception, even though the majority belong to the middle class. Such is the reality of competition. The rat race ensures there will always be a distinction between the rich/poor, academically superior/inferior, the private property owners/HDB heartlanders...you get the idea.
In other countries, it's even more pronounced and formally/socially delineated.
Think of the House of Lords in the UK and the passing down of hereditary titles. Or those who are knighted/mentioned in the Queen's Honours list with their OBEs and MBEs and CBEs.
Or in India with the brahmans and untouchables, or in Japan and South Korea with rigid social hierarchies, or countries with monarchies. Closer to home, Malaysia has its sultans and King, its datohs and datins, while ordinary Thais are not supposed to look at the Thai King directly. Human beings are NOT created equal (or maybe I should say some are more equal than others hehe)....some are born with a silver sppon, and some naturally achieve more than others in their lifetimes.
Generally, Singaporeans have an easier time in my opinion. Class distinction here is a question of mindset, and decided over material things in most cases. Perhaps education, humility, and a greater compassion for those less fortunate can lessen this *growing* phenomenon in the future.
Rich or poor, everyone deserves respect and dignity- but people should not be under the illusion that class distinction can be erased. To end on a positive note however, people who flaunt their superiority (wealth, intelligence, material posessions) blatantly demonstrate very little 'class' even if they think they are in a class of their own. HEHE!