Singapore is also an island that is ~twice as wealthy as the UK per capita. I believe you in general but I'd love a lower-income country that could be true for.
High trust builds wealth - thus what you ask is a direct contradiction of the thesis. There is a lot of 'well' and details of what high trust means, but low trust doesn't allow for many wealth building investments - there is no possible way to make a better life (money is only a proxy) so few try and those that do are worse off.
