It's true that they were very well compensated for the work. I think it's worth keeping in mind, though, that controlling a large group of cultural natives who

It's true that they were very well compensated for the work. I think it's worth keeping in mind, though, that controlling a large group of cultural natives who've integrated into your cultural leaves a lot of room open for further benefits on both sides of the equation. Of course, that way lies empire - maybe you don't want to take the trouble. But I think the real reason we don't do it (the reason that the author of this piece brings up and then, rather oddly to my mind, dismisses) is that career politics doesn't reward building up long-term assets (outside of some very specialized circumstances), whereas it most certainly does punish 'letting in the wrong people'. There's little incentive to take the initiative if you haven't already been given an order.