[refurb]

You have to be careful looking at GDP per capita. That money doesn't always stay within the country, especially with tax havens.

Look at Ireland's GDP per capita - it's on par with Singapore! But a lot of that is due to the tax strategies of companies like Google that park their IP in Ireland, then "sell" it to countries in Europe. That's all GDP for Ireland. But what happens to the money? It gets pumped back to the US.

It's similar with Singapore. There are huge refineries, and pharmaceutical manufacturing on the island. The country makes these product (often of high value), which contributes to the GDP. But that money exits the country (save for the workers in Singapore) back to the HQ country.

If you look at median wages in Singapore, you'll get a much better sense of the wealth. But do note that the number the Singaporean government quotes doesn't include the 40% of the population that is migrant workers - it's only Singaporean citizens and PRs. So it ignores the bottom ~40% of workers (save for the highly skill people on work passes).