Singapore had no resources other than the brains of its people; they were the underclass who were booted out of Malaysia with just the shirts on their backs.
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