Or,
just postulating here,
maybe the capital that is transmitted is just that. Capital.
That and tribalism/nepotism could explain these results as well.
Malays have little to do with Singapore's economy.
Han Chinese are not Malays. From Appendix 1 of "IQ and the Wealth of Nations" by Lynn & Vanhanen (p218):
Singapore
In 1974, data for a representative sample of 147 ethnic Chinese and 190 ethnic Malay 13-year-olds for the Standard Progressive Matrices were collected (Lynn, 1976). In relation to the British 1979 standardization sample, the Chinese obtained a mean IQ of 106 and the Malays a mean IQ of 90.5. ... The population of Singapore is 76 percent Chinese, 14 percent Malay, and 7 percent Indian