Keeping your dictators benevolent across decades and generations has proven a significantly hard problem. Even that give this form of government, in my view, far far too much credit.

Singapore is a rare contemporary example of a city-state, & I think that makes the scenario very different from most cases. Using this as an example seems ill suited.

Let's compare to one of your other cited cases, Philippines. Both experienced to degrees the wave of modernization following WW2, a moment of great possibility. Singapore is a very small nation, 1/4 the size of the smallest US State, Rhode Island. Sinagpore is positioned nicely amid a number of other countries giving it close trade access, and at the sea-most tip of a major intercontinental route. The Philippines is almost 100x bigger, about on par with Nevada, the 7th largest state, with much more space & population to tend to. Philippines is non-continugous in extreme, a nation of many islands, further exarcerbating the difficulty of effective governance. Philippines are isolated by a couple hundred miles of sea from other nations, and located rather at the edge of the map.

Singapore is one of the few city-states left on this planet, and it was one permitted to strain & grow at a crucial inflection point in human history.