All except Kuok Khoon Hong got their wealth either through property, usury, speculation, or inheritance. Even for Kuok Khoon Hong, his success is probably more due to his rich uncle Robert Kuok, than bullshit like hard work.
The rich in Singapore are there not because they have create value for society, but due to PAP's policy of asset inflation, transferring wealth from productive citizen to rentier elites. Singapore is the least meritocratic society in the world. Nevertheless, PAP propaganda is successful in convincing many gullible slave citizen.
Now you know why we must pay 30 years housing loan for 99 years HDB.
Above: The German richest not only pay one of the world highest tax, in addition, their companies create jobs, values, and add-on to technological know-how. Non of their primary business is property.