The location is good, but there are many strategically well located places that are poor today. The people aren’t meaningfully different than the countries around Singapore. A 75% Chinese supermajority, maintained for decades through selective immigration controls. But China itself was as poor as India into the 1990s, while Singapore was rapidly developing long before then.
LKY chalked it up to good, pragmatic policies implemented in a culturally sensitive way: https://paulbacon.wordpress.com/wp-content/uploads/2010/04/z.... (Read the whole thing. The first part is about culture, while the second part starting on p. 114 is about how he implemented western economic policies without trying to import western style social policies.) Singapore focused on neoliberalism within a social and cultural framework that accommodates the Chinese, Malay, and Indian communities that compose the country. It focused on anti-corruption and government efficiency, a major weak spot of nearly all developing countries. But it didn’t try to go straight from fishing village to liberal democracy. Like other countries that developed rapidly in Asia (Taiwan, Japan, South Korea, and now China) development of state capacity and civil institutions happened under soft-authoritarian, one-party rule.
To put it in one sentence: LKY was a bog standard neoliberal who didn’t suffer from the neoconservative delusion that American-style individual rights and populist democracy can be transplanted into any country hand-in-hand with neoliberal economic policies.