> If people don't invest locally, wages will fall until they've fallen enough that it's profitable to invest locally.
The problem with toy economic models like yours is that they're toys, and the elide many important factors in the name of simplicity. That simplicity can be extremely intellectually compelling, especially for laymen, but at the end of the day the world is complex and if you ignore that you have bad policy.
When all you have is a hammer, every problem looks like a nail. The solution to market failures is not more and harder market.
> There's no scenario in which investment dries up.
The literal facts are against you. The banks withdrew and American Samoans have no access to credit outside of usurious backyard moneylenders.
> Now, in order for economic health, the investments made have to be put towards doing useful things. Ideally, very useful things.
What at all does this have to do with anything under discussion? Usefulness is a local function and the precise problem here is that American Samoans (and others) don't have access to the credit they need do useful things in their communities. I'll bet you money that they're not planning to take out loans to do useless things like dig and fill in holes.
Anyway, I think we're talking past each other, and you seem more interested in performing dogma.