SAO PAULO, Brazil — Lino Quispelaura left his impoverished neighborhood in Bolivia’s capital two years ago, hoping to earn enough money in neighboring Brazil to come back a rich man. After crossing the width of South America and settling in sprawling Sao Paulo, however, such hopes seem far away for Quispelaura, even farther than his mountainous homeland. Like tens of thousands of other Bolivians here, Quispelaura has sunk into a grinding routine of nonstop, low-paid labor. He wakes before 7 a.m. every day to sew in a cramped garment factory until late at night, then sleeps on a mattress near his sewing machine. He earns barely enough to survive, and if he complains his bosses threaten to have him deported. ‘No matter what people say, it’s hard to get used to this life,’ Quispelaura, 20, said on one of his rare days off. ‘Coming here would have been worth the trouble if life were a little better than before. But I’m not sure it was worth the trouble.’ Driven by dire poverty and political instability in South America’s poorest country, Bolivians now make up one of the biggest cross-border movements of people in the region. […]