There was significant interest from foreign powers doing just that, look up Operation Coldstore and the history of communist insurgency in Singapore.
And of course the right wingers not only had "heavy foreign influence and support" on their side too (the whole country was established under heavy western influence and at its "benevolence"), but they also crushed them, undemocratically with the help of that foreign influence and support.
Doesn't work if you're just a land with resources to plunder and they have no interests in seeing you thrive, but the contrary.
Works even less if you have other ideas about your governance, trade, and allies that suit you, to what powerful countries taking an interest in your area want you to have because it suits them.
But if you don't have resources for them to covet, your existence fits a purpose in their plans, and you don't get too independent but always keep their preferences in mind, yeah, you can then apply leadership to make things better.
It's just leadership in much easier circumstances than elsewhere.
The biggest asset, aside from being a port on a great location, was the right alliances, and foreign countries being the island being let mostly alone, and you not having valuable resources, plus the desire of the rich in countries around the area to use the island as a tax haven of sorts (and later, as their comfy home away from home).
Yew would have been thrown out of office in a week and some "coup" would have been organized if some big foreign power has special interests in the area and wanted him gone.
And if the island had resources like oil or such, it would have been invaded, occupied, "liberated" by some new traiting politician friendly to the outside, every second year.