How did they get the buying power in the first place?

Jobs of some sort. Teachers, construction workers, health care workers, programmers. Farmers, utility workers, electricians and craftsmen of different sorts. Case workers for the country's child protection agency. Folks that speak the local language who work in call centers. Sure, some of these are low-paying jobs, but lets face it: so are some factory jobs (i've worked in one and had friend that worked in others, which pay a little above minimum wage).

Simply put, you aren't going to ship off all the jobs. So they aren't the best at manufacturing? So what? Obviously, if they have buying power, the country has some other strengths. They simply wouldn't show up when looking at manufacturing only.