There are a number of small town jobs where this can be true, even what some might consider 'temp' work like waitstaff or gardener. There are of course the 'professional' careers, like lawyer, doctor, or accountant, and of course civil jobs like police officer, firefighter, clerk.
The interesting bit comes when you're thinking about investing, say to build a gas station or a wallmart, knowing that the population will be relatively stable is an incentive.
They don't constrain where the kids go, they can go to any school that they are accepted to AFAICT from the article. So some schools might recruit them knowing they won't need financial aid.
It is a fascinating experiment in so many ways.